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

testing/ef_tests/src/cases/transition.rs

@@ -37,6 +37,9 @@ impl<E: EthSpec> LoadCase for TransitionTest<E> {
             ForkName::Altair => {
                 spec.altair_fork_epoch = Some(metadata.fork_epoch);
             }
+            ForkName::Merge => {
+                spec.merge_fork_epoch = Some(metadata.fork_epoch);
+            }
         }
 
         // Load blocks