* [NOD-1496] Implement headers only verification
* [NOD-1496] Add checkParentsExist
* [NOD-1496] Stage block statuses in block processor
* [NOD-1496] Rename AddBlock->AddHeaderTip
* [NOD-1496] Return early from validateAndInsertBlock on header only and put ValidateProofOfWorkAndDifficulty inside validateBlock
* [NOD-1461] Change the external api interface to not having anything besides DomainTransactions and DomainBlocks.
* [NOD-1462] Move external api types to a separate package.
* [NOD-1462] Clarify which model we're using in miningmanager.
* [NOD-1462] Extract coinbase data to its own struct.
* [NOD-1462] Add a comment above CoinbaseData.
* [NOD-1462] Fix the comment above CoinbaseData.