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/handler.rs

@@ -34,6 +34,7 @@ pub trait Handler {
         let fork_name_str = match fork_name {
             ForkName::Base => "phase0",
             ForkName::Altair => "altair",
+            ForkName::Merge => "merge", // TODO: check this
         };
 
         let handler_path = PathBuf::from(env!("CARGO_MANIFEST_DIR"))