Move beacon pool http api to its own separate module (#8543)

Continuation of:
* #8536

Moving `/beacon/pool` endpoints out of `http_api` to a separation module. This should improve code maintainability, incremental compilation time and rust analyzer performance.

This is a tedious but straight forward change, so we're going with a pair & insta-merge approach to avoid painful & slow async review


  


Co-Authored-By: Jimmy Chen <jchen.tc@gmail.com>

beacon_node/http_api/src/utils.rs

@@ -7,7 +7,7 @@ use network::{NetworkMessage, ValidatorSubscriptionMessage};
 use parking_lot::RwLock;
 use std::sync::Arc;
 use tokio::sync::mpsc::{Sender, UnboundedSender};
-use types::{ChainSpec, EthSpec};
+use types::{ChainSpec, EthSpec, ForkName};
 use warp::Rejection;
 use warp::filters::BoxedFilter;
 
@@ -20,6 +20,7 @@ pub type TaskSpawnerFilter<T> = BoxedFilter<(TaskSpawner<<T as BeaconChainTypes>
 pub type ValidatorSubscriptionTxFilter = BoxedFilter<(Sender<ValidatorSubscriptionMessage>,)>;
 pub type NetworkTxFilter<T> =
     BoxedFilter<(UnboundedSender<NetworkMessage<<T as BeaconChainTypes>::EthSpec>>,)>;
+pub type OptionalConsensusVersionHeaderFilter = BoxedFilter<(Option<ForkName>,)>;
 
 pub fn from_meta_data<E: EthSpec>(
     meta_data: &RwLock<MetaData<E>>,