Refactor consensus/types (#7827)

Organize and categorize `consensus/types` into modules based on their relation to key consensus structures/concepts.
This is a precursor to a sensible public interface.

While this refactor is very opinionated, I am open to suggestions on module names, or type groupings if my current ones are inappropriate.


Co-Authored-By: Mac L <mjladson@pm.me>

beacon_node/lighthouse_network/src/rpc/methods.rs

@@ -5,7 +5,7 @@ use regex::bytes::Regex;
 use serde::Serialize;
 use ssz::Encode;
 use ssz_derive::{Decode, Encode};
-use ssz_types::{VariableList, typenum::U256};
+use ssz_types::{RuntimeVariableList, VariableList, typenum::U256};
 use std::fmt::Display;
 use std::marker::PhantomData;
 use std::ops::Deref;
@@ -17,7 +17,7 @@ use types::light_client_update::MAX_REQUEST_LIGHT_CLIENT_UPDATES;
 use types::{
     ChainSpec, ColumnIndex, DataColumnSidecar, DataColumnsByRootIdentifier, Epoch, EthSpec,
     ForkContext, Hash256, LightClientBootstrap, LightClientFinalityUpdate,
-    LightClientOptimisticUpdate, LightClientUpdate, RuntimeVariableList, SignedBeaconBlock, Slot,
+    LightClientOptimisticUpdate, LightClientUpdate, SignedBeaconBlock, Slot,
     blob_sidecar::BlobSidecar,
 };