Remove consensus/types re-exports (#8540)

There are certain crates which we re-export within `types` which creates a fragmented DevEx, where there are various ways to import the same crates.

```rust
// consensus/types/src/lib.rs
pub use bls::{
AggregatePublicKey, AggregateSignature, Error as BlsError, Keypair, PUBLIC_KEY_BYTES_LEN,
PublicKey, PublicKeyBytes, SIGNATURE_BYTES_LEN, SecretKey, Signature, SignatureBytes,
get_withdrawal_credentials,
};
pub use context_deserialize::{ContextDeserialize, context_deserialize};
pub use fixed_bytes::FixedBytesExtended;
pub use milhouse::{self, List, Vector};
pub use ssz_types::{BitList, BitVector, FixedVector, VariableList, typenum, typenum::Unsigned};
pub use superstruct::superstruct;
```

This PR removes these re-exports and makes it explicit that these types are imported from a non-`consensus/types` crate.


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

consensus/proto_array/src/proto_array_fork_choice.rs

@@ -7,6 +7,7 @@ use crate::{
     },
     ssz_container::SszContainer,
 };
+use fixed_bytes::FixedBytesExtended;
 use serde::{Deserialize, Serialize};
 use ssz::{Decode, Encode};
 use ssz_derive::{Decode, Encode};
@@ -15,8 +16,8 @@ use std::{
     fmt,
 };
 use types::{
-    AttestationShufflingId, ChainSpec, Checkpoint, Epoch, EthSpec, ExecutionBlockHash,
-    FixedBytesExtended, Hash256, Slot,
+    AttestationShufflingId, ChainSpec, Checkpoint, Epoch, EthSpec, ExecutionBlockHash, Hash256,
+    Slot,
 };
 
 pub const DEFAULT_PRUNE_THRESHOLD: usize = 256;
@@ -1095,7 +1096,8 @@ fn compute_deltas(
 #[cfg(test)]
 mod test_compute_deltas {
     use super::*;
-    use types::{FixedBytesExtended, MainnetEthSpec};
+    use fixed_bytes::FixedBytesExtended;
+    use types::MainnetEthSpec;
 
     /// Gives a hash that is not the zero hash (unless i is `usize::MAX)`.
     fn hash_from_index(i: usize) -> Hash256 {