Create BlockProcessorV0 which handles the genesis block

[shuse2]

Description

Add block processor v0 to process genesis block by implementing below steps according to the LIP:

• Validate step
  • header.generatorPublicKey must be empty
  • header.reward must be zero
  • header.signature must be empty
  • header.asset.initDelegates must be array of account addresses
  • Those account must exists in header.asset.accounts and must be a delegate
  • The list should have minimum 1 element
  • The list should have maximum ROUND_LENGTH (active + standby delegates) elements
  • header.asset.initRounds should be minimum 3
  • Genesis block should be considered as zero round, direct child of this genesis block must be first block of a round
• Apply step
  • Save accounts
  • Save initDelegates

Motivation

New genesis block needs to be processed differently from other blocks.

Acceptance Criteria

• Add unit test for the validation and apply

Additional Information

Related issues: #5234