Self rate limiting dev flag (#3928)

## Issue Addressed
Adds self rate limiting options, mainly with the idea to comply with peer's rate limits in small testnets

## Proposed Changes
Add a hidden flag `self-limiter` this can take no value, or customs values to configure quotas per protocol

## Additional Info
### How to use
`--self-limiter` will turn on the self rate limiter applying the same params we apply to inbound requests (requests from other peers)
`--self-limiter "beacon_blocks_by_range:64/1"` will turn on the self rate limiter for ALL protocols, but change the quota for bbrange to 64 requested blocks per 1 second.
`--self-limiter "beacon_blocks_by_range:64/1;ping:1/10"` same as previous one, changing the quota for ping as well.

### Caveats
- The rate limiter is either on or off for all protocols. I added the custom values to be able to change the quotas per protocol so that some protocols can be given extremely loose or tight quotas. I think this should satisfy every need even if we can't technically turn off rate limits per protocol.
- This reuses the rate limiter struct for the inbound requests so there is this ugly part of the code in which we need to deal with the inbound only protocols (light client stuff) if this becomes too ugly as we add lc protocols, we might want to split the rate limiters. I've checked this and looks doable with const generics to avoid so much code duplication

### Knowing if this is on
```
Feb 06 21:12:05.493 DEBG Using self rate limiting params         config: OutboundRateLimiterConfig { ping: 2/10s, metadata: 1/15s, status: 5/15s, goodbye: 1/10s, blocks_by_range: 1024/10s, blocks_by_root: 128/10s }, service: libp2p_rpc, service: libp2p
```

beacon_node/lighthouse_network/src/rpc/config.rs

@@ -0,0 +1,173 @@
+use std::{
+    fmt::{Debug, Display},
+    str::FromStr,
+    time::Duration,
+};
+
+use super::{methods, rate_limiter::Quota, Protocol};
+
+use serde_derive::{Deserialize, Serialize};
+
+/// Auxiliary struct to aid on configuration parsing.
+///
+/// A protocol's quota is specified as `protocol_name:tokens/time_in_seconds`.
+#[derive(Debug, PartialEq, Eq)]
+struct ProtocolQuota {
+    protocol: Protocol,
+    quota: Quota,
+}
+
+impl Display for ProtocolQuota {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "{}:{}/{}",
+            self.protocol.as_ref(),
+            self.quota.max_tokens,
+            self.quota.replenish_all_every.as_secs()
+        )
+    }
+}
+
+impl FromStr for ProtocolQuota {
+    type Err = &'static str;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let (protocol_str, quota_str) = s
+            .split_once(':')
+            .ok_or("Missing ':' from quota definition.")?;
+        let protocol = protocol_str
+            .parse()
+            .map_err(|_parse_err| "Wrong protocol representation in quota")?;
+        let (tokens_str, time_str) = quota_str
+            .split_once('/')
+            .ok_or("Quota should be defined as \"n/t\" (t in seconds). Missing '/' from quota.")?;
+        let tokens = tokens_str
+            .parse()
+            .map_err(|_| "Failed to parse tokens from quota.")?;
+        let seconds = time_str
+            .parse::<u64>()
+            .map_err(|_| "Failed to parse time in seconds from quota.")?;
+        Ok(ProtocolQuota {
+            protocol,
+            quota: Quota {
+                replenish_all_every: Duration::from_secs(seconds),
+                max_tokens: tokens,
+            },
+        })
+    }
+}
+
+/// Configurations for the rate limiter applied to outbound requests (made by the node itself).
+#[derive(Clone, Serialize, Deserialize, PartialEq, Eq)]
+pub struct OutboundRateLimiterConfig {
+    pub(super) ping_quota: Quota,
+    pub(super) meta_data_quota: Quota,
+    pub(super) status_quota: Quota,
+    pub(super) goodbye_quota: Quota,
+    pub(super) blocks_by_range_quota: Quota,
+    pub(super) blocks_by_root_quota: Quota,
+}
+
+impl OutboundRateLimiterConfig {
+    pub const DEFAULT_PING_QUOTA: Quota = Quota::n_every(2, 10);
+    pub const DEFAULT_META_DATA_QUOTA: Quota = Quota::n_every(2, 5);
+    pub const DEFAULT_STATUS_QUOTA: Quota = Quota::n_every(5, 15);
+    pub const DEFAULT_GOODBYE_QUOTA: Quota = Quota::one_every(10);
+    pub const DEFAULT_BLOCKS_BY_RANGE_QUOTA: Quota =
+        Quota::n_every(methods::MAX_REQUEST_BLOCKS, 10);
+    pub const DEFAULT_BLOCKS_BY_ROOT_QUOTA: Quota = Quota::n_every(128, 10);
+}
+
+impl Default for OutboundRateLimiterConfig {
+    fn default() -> Self {
+        OutboundRateLimiterConfig {
+            ping_quota: Self::DEFAULT_PING_QUOTA,
+            meta_data_quota: Self::DEFAULT_META_DATA_QUOTA,
+            status_quota: Self::DEFAULT_STATUS_QUOTA,
+            goodbye_quota: Self::DEFAULT_GOODBYE_QUOTA,
+            blocks_by_range_quota: Self::DEFAULT_BLOCKS_BY_RANGE_QUOTA,
+            blocks_by_root_quota: Self::DEFAULT_BLOCKS_BY_ROOT_QUOTA,
+        }
+    }
+}
+
+impl Debug for OutboundRateLimiterConfig {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        macro_rules! fmt_q {
+            ($quota:expr) => {
+                &format_args!(
+                    "{}/{}s",
+                    $quota.max_tokens,
+                    $quota.replenish_all_every.as_secs()
+                )
+            };
+        }
+
+        f.debug_struct("OutboundRateLimiterConfig")
+            .field("ping", fmt_q!(&self.ping_quota))
+            .field("metadata", fmt_q!(&self.meta_data_quota))
+            .field("status", fmt_q!(&self.status_quota))
+            .field("goodbye", fmt_q!(&self.goodbye_quota))
+            .field("blocks_by_range", fmt_q!(&self.blocks_by_range_quota))
+            .field("blocks_by_root", fmt_q!(&self.blocks_by_root_quota))
+            .finish()
+    }
+}
+
+/// Parse configurations for the outbound rate limiter. Protocols that are not specified use
+/// the default values. Protocol specified more than once use only the first given Quota.
+///
+/// The expected format is a ';' separated list of [`ProtocolQuota`].
+impl FromStr for OutboundRateLimiterConfig {
+    type Err = &'static str;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut ping_quota = None;
+        let mut meta_data_quota = None;
+        let mut status_quota = None;
+        let mut goodbye_quota = None;
+        let mut blocks_by_range_quota = None;
+        let mut blocks_by_root_quota = None;
+        for proto_def in s.split(';') {
+            let ProtocolQuota { protocol, quota } = proto_def.parse()?;
+            let quota = Some(quota);
+            match protocol {
+                Protocol::Status => status_quota = status_quota.or(quota),
+                Protocol::Goodbye => goodbye_quota = goodbye_quota.or(quota),
+                Protocol::BlocksByRange => blocks_by_range_quota = blocks_by_range_quota.or(quota),
+                Protocol::BlocksByRoot => blocks_by_root_quota = blocks_by_root_quota.or(quota),
+                Protocol::Ping => ping_quota = ping_quota.or(quota),
+                Protocol::MetaData => meta_data_quota = meta_data_quota.or(quota),
+                Protocol::LightClientBootstrap => return Err("Lighthouse does not send LightClientBootstrap requests. Quota should not be set."),
+            }
+        }
+        Ok(OutboundRateLimiterConfig {
+            ping_quota: ping_quota.unwrap_or(Self::DEFAULT_PING_QUOTA),
+            meta_data_quota: meta_data_quota.unwrap_or(Self::DEFAULT_META_DATA_QUOTA),
+            status_quota: status_quota.unwrap_or(Self::DEFAULT_STATUS_QUOTA),
+            goodbye_quota: goodbye_quota.unwrap_or(Self::DEFAULT_GOODBYE_QUOTA),
+            blocks_by_range_quota: blocks_by_range_quota
+                .unwrap_or(Self::DEFAULT_BLOCKS_BY_RANGE_QUOTA),
+            blocks_by_root_quota: blocks_by_root_quota
+                .unwrap_or(Self::DEFAULT_BLOCKS_BY_ROOT_QUOTA),
+        })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_quota_inverse() {
+        let quota = ProtocolQuota {
+            protocol: Protocol::Goodbye,
+            quota: Quota {
+                replenish_all_every: Duration::from_secs(10),
+                max_tokens: 8,
+            },
+        };
+        assert_eq!(quota.to_string().parse(), Ok(quota))
+    }
+}