Modularize validator store (#6705)

- Create trait `ValidatorStore` with all functions used by the `validator_services`
- Make `validator_services` generic on `S: ValidatorStore`
- Introduce `LighthouseValidatorStore`, which has identical functionality to the old `ValidatorStore`
- Remove dependencies (especially `environment`) from `validator_services` and `beacon_node_fallback` in order to be able to cleanly use them in Anchor

consensus/types/src/attestation.rs

@@ -16,7 +16,7 @@ use super::{
     Signature, SignedRoot,
 };
 
-#[derive(Debug, PartialEq)]
+#[derive(Debug, PartialEq, Clone)]
 pub enum Error {
     SszTypesError(ssz_types::Error),
     BitfieldError(ssz::BitfieldError),

consensus/types/src/payload.rs

@@ -85,6 +85,7 @@ pub trait AbstractExecPayload<E: EthSpec>:
     + TryInto<Self::Deneb>
     + TryInto<Self::Electra>
     + TryInto<Self::Fulu>
+    + Sync
 {
     type Ref<'a>: ExecPayload<E>
         + Copy
@@ -97,23 +98,28 @@ pub trait AbstractExecPayload<E: EthSpec>:
     type Bellatrix: OwnedExecPayload<E>
         + Into<Self>
         + for<'a> From<Cow<'a, ExecutionPayloadBellatrix<E>>>
-        + TryFrom<ExecutionPayloadHeaderBellatrix<E>>;
+        + TryFrom<ExecutionPayloadHeaderBellatrix<E>>
+        + Sync;
     type Capella: OwnedExecPayload<E>
         + Into<Self>
         + for<'a> From<Cow<'a, ExecutionPayloadCapella<E>>>
-        + TryFrom<ExecutionPayloadHeaderCapella<E>>;
+        + TryFrom<ExecutionPayloadHeaderCapella<E>>
+        + Sync;
     type Deneb: OwnedExecPayload<E>
         + Into<Self>
         + for<'a> From<Cow<'a, ExecutionPayloadDeneb<E>>>
-        + TryFrom<ExecutionPayloadHeaderDeneb<E>>;
+        + TryFrom<ExecutionPayloadHeaderDeneb<E>>
+        + Sync;
     type Electra: OwnedExecPayload<E>
         + Into<Self>
         + for<'a> From<Cow<'a, ExecutionPayloadElectra<E>>>
-        + TryFrom<ExecutionPayloadHeaderElectra<E>>;
+        + TryFrom<ExecutionPayloadHeaderElectra<E>>
+        + Sync;
     type Fulu: OwnedExecPayload<E>
         + Into<Self>
         + for<'a> From<Cow<'a, ExecutionPayloadFulu<E>>>
-        + TryFrom<ExecutionPayloadHeaderFulu<E>>;
+        + TryFrom<ExecutionPayloadHeaderFulu<E>>
+        + Sync;
 }
 
 #[superstruct(