Integrate tracing (#6339)

Tracing Integration
- [reference](5bbf1859e9/projects/project-ideas.md (L297))


  - [x] replace slog & log with tracing throughout the codebase
- [x] implement custom crit log
- [x] make relevant changes in the formatter
- [x] replace sloggers
- [x] re-write SSE logging components

cc: @macladson @eserilev

beacon_node/lighthouse_network/src/discovery/subnet_predicate.rs

@@ -1,22 +1,19 @@
 //! The subnet predicate used for searching for a particular subnet.
 use super::*;
 use crate::types::{EnrAttestationBitfield, EnrSyncCommitteeBitfield};
-use slog::trace;
 use std::ops::Deref;
+use tracing::trace;
 use types::data_column_custody_group::compute_subnets_for_node;
 use types::ChainSpec;
 
 /// Returns the predicate for a given subnet.
 pub fn subnet_predicate<E>(
     subnets: Vec<Subnet>,
-    log: &slog::Logger,
     spec: Arc<ChainSpec>,
 ) -> impl Fn(&Enr) -> bool + Send
 where
     E: EthSpec,
 {
-    let log_clone = log.clone();
-
     move |enr: &Enr| {
         let attestation_bitfield: EnrAttestationBitfield<E> = match enr.attestation_bitfield::<E>()
         {
@@ -48,9 +45,8 @@ where
 
         if !predicate {
             trace!(
-                log_clone,
-                "Peer found but not on any of the desired subnets";
-                "peer_id" => %enr.peer_id()
+                peer_id = %enr.peer_id(),
+                "Peer found but not on any of the desired subnets"
             );
         }
         predicate