Implement afterBlockExecute hook for DPoS module

[mehmetegemen]

Description

Bundle 3 topics from their respective private functions in the hook:

• Implement updateDelegateProductivity for DPoS Module #6874
• Implement createVoteWeightSnapshot for DPoS Module #6875
• Implement updateValidators for DPoS Module #6876

and implement necessary conditionals while implementing these functions(e.g. some portion of the code should work after bootstrap period or at the last block of round). Private functions must use reusable auxilary function that contains the actual logic of the topic.

Also update previousTimestampStore on successful forging and implement anything related to hook that is outside of reusable logic. And add unit tests.

Acceptance Criteria

• Unit tests must pass

Additional Information

• Code must use new module APIs and as much as the old DPoS module code