* ForkedChainRef.forkchoice: Skip newBase calculation and skip chain finalization if finalizedHash is zero
* Fix ForkedChainRef.forkChoice: do nothing if headHash is the same with cursorHash
* Fix stupid bug in engine API FCU when calling ForkedChainRef.forkChoice
* Wire RPC server API to nimbus RPC manager
* Add test case
* Use default(Hash256) in ForkedChainRef
andri lim