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/common.rs

@@ -77,5 +77,6 @@ pub fn previous_fork(fork_name: ForkName) -> ForkName {
     match fork_name {
         ForkName::Base => ForkName::Base,
         ForkName::Altair => ForkName::Base,
+        ForkName::Merge => ForkName::Altair, // TODO: Check this when tests are released..
     }
 }