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>

beacon_node/beacon_chain/src/validator_monitor.rs

@@ -4,6 +4,7 @@
 
 use crate::beacon_proposer_cache::{BeaconProposerCache, TYPICAL_SLOTS_PER_EPOCH};
 use crate::metrics;
+use bls::PublicKeyBytes;
 use itertools::Itertools;
 use logging::crit;
 use parking_lot::{Mutex, RwLock};
@@ -28,9 +29,10 @@ use types::consts::altair::{
 use types::{
     Attestation, AttestationData, AttesterSlashingRef, BeaconBlockRef, BeaconState,
     BeaconStateError, ChainSpec, Epoch, EthSpec, Hash256, IndexedAttestation,
-    IndexedAttestationRef, ProposerSlashing, PublicKeyBytes, SignedAggregateAndProof,
-    SignedContributionAndProof, Slot, SyncCommitteeMessage, VoluntaryExit,
+    IndexedAttestationRef, ProposerSlashing, SignedAggregateAndProof, SignedContributionAndProof,
+    Slot, SyncCommitteeMessage, VoluntaryExit,
 };
+
 /// Used for Prometheus labels.
 ///
 /// We've used `total` for this value to align with Nimbus, as per: