* ForkedChain implementation
- revamp test_blockchain_json using ForkedChain
- re-enable previously failing test cases.
* Remove excess error handling
* Avoid reloading parent header
* Do not force base update
* Write baggage to database
* Add findActiveChain to finalizedSegment
* Create new stagingTx in addBlock
* Check last stateRoot existence in test_blockchain_json
* Resolve rebase conflict
* More precise nomenclature for block import cursor
* Ensure bad block nor imported and good block not rejected
* finalizeSegment become forkChoice and align with engine API forkChoice spec
* Display reason when good block rejected
* Fix comments
* Put BaseDistance into CalculateNewBase equation
* Separate finalizedHash from baseHash
* Add more doAssert constraint
* Add push raises: []