Initial merge changes

Added Execution Payload from Rayonism Fork

Updated new Containers to match Merge Spec

Updated BeaconBlockBody for Merge Spec

Completed updating BeaconState and BeaconBlockBody

Modified ExecutionPayload<T> to use Transaction<T>

Mostly Finished Changes for beacon-chain.md

Added some things for fork-choice.md

Update to match new fork-choice.md/fork.md changes

ran cargo fmt

Added Missing Pieces in eth2_libp2p for Merge

fix ef test

Various Changes to Conform Closer to Merge Spec

beacon_node/store/src/hot_cold_store.rs

@@ -883,6 +883,10 @@ impl<E: EthSpec, Hot: ItemStore<E>, Cold: ItemStore<E>> HotColdDB<E, Hot, Cold>
                         &mut block.message.state_root,
                         &mut block.message.parent_root,
                     ),
+                    SignedBeaconBlock::Merge(block) => (
+                        &mut block.message.state_root,
+                        &mut block.message.parent_root,
+                    ),
                 };
 
                 *state_root = Hash256::zero();

beacon_node/store/src/partial_beacon_state.rs

@@ -14,8 +14,8 @@ use types::*;
 ///
 /// Utilises lazy-loading from separate storage for its vector fields.
 #[superstruct(
-    variants(Base, Altair),
-    variant_attributes(derive(Debug, PartialEq, Clone, Encode, Decode),)
+    variants(Base, Altair, Merge),
+    variant_attributes(derive(Debug, PartialEq, Clone, Encode, Decode))
 )]
 #[derive(Debug, PartialEq, Clone, Encode)]
 #[ssz(enum_behaviour = "transparent")]
@@ -66,9 +66,9 @@ where
     pub current_epoch_attestations: VariableList<PendingAttestation<T>, T::MaxPendingAttestations>,
 
     // Participation (Altair and later)
-    #[superstruct(only(Altair))]
+    #[superstruct(only(Altair, Merge))]
     pub previous_epoch_participation: VariableList<ParticipationFlags, T::ValidatorRegistryLimit>,
-    #[superstruct(only(Altair))]
+    #[superstruct(only(Altair, Merge))]
     pub current_epoch_participation: VariableList<ParticipationFlags, T::ValidatorRegistryLimit>,
 
     // Finality
@@ -78,14 +78,18 @@ where
     pub finalized_checkpoint: Checkpoint,
 
     // Inactivity
-    #[superstruct(only(Altair))]
+    #[superstruct(only(Altair, Merge))]
     pub inactivity_scores: VariableList<u64, T::ValidatorRegistryLimit>,
 
     // Light-client sync committees
-    #[superstruct(only(Altair))]
+    #[superstruct(only(Altair, Merge))]
     pub current_sync_committee: Arc<SyncCommittee<T>>,
-    #[superstruct(only(Altair))]
+    #[superstruct(only(Altair, Merge))]
     pub next_sync_committee: Arc<SyncCommittee<T>>,
+
+    // Execution
+    #[superstruct(only(Merge))]
+    pub latest_execution_payload_header: ExecutionPayloadHeader<T>,
 }
 
 /// Implement the conversion function from BeaconState -> PartialBeaconState.
@@ -160,6 +164,20 @@ impl<T: EthSpec> PartialBeaconState<T> {
                     inactivity_scores
                 ]
             ),
+            BeaconState::Merge(s) => impl_from_state_forgetful!(
+                s,
+                outer,
+                Merge,
+                PartialBeaconStateMerge,
+                [
+                    previous_epoch_participation,
+                    current_epoch_participation,
+                    current_sync_committee,
+                    next_sync_committee,
+                    inactivity_scores,
+                    latest_execution_payload_header
+                ]
+            ),
         }
     }
 
@@ -334,6 +352,19 @@ impl<E: EthSpec> TryInto<BeaconState<E>> for PartialBeaconState<E> {
                     inactivity_scores
                 ]
             ),
+            PartialBeaconState::Merge(inner) => impl_try_into_beacon_state!(
+                inner,
+                Merge,
+                BeaconStateMerge,
+                [
+                    previous_epoch_participation,
+                    current_epoch_participation,
+                    current_sync_committee,
+                    next_sync_committee,
+                    inactivity_scores,
+                    latest_execution_payload_header
+                ]
+            ),
         };
         Ok(state)
     }