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/errors.rs

@@ -9,9 +9,11 @@ use crate::observed_aggregates::Error as ObservedAttestationsError;
 use crate::observed_attesters::Error as ObservedAttestersError;
 use crate::observed_block_producers::Error as ObservedBlockProducersError;
 use crate::observed_data_sidecars::Error as ObservedDataSidecarsError;
+use bls::PublicKeyBytes;
 use execution_layer::PayloadStatus;
 use fork_choice::ExecutionStatus;
 use futures::channel::mpsc::TrySendError;
+use milhouse::Error as MilhouseError;
 use operation_pool::OpPoolError;
 use safe_arith::ArithError;
 use ssz_types::Error as SszTypesError;
@@ -28,7 +30,6 @@ use state_processing::{
 };
 use task_executor::ShutdownReason;
 use tokio::task::JoinError;
-use types::milhouse::Error as MilhouseError;
 use types::*;
 
 macro_rules! easy_from_to {