[EPOCH TRANSITION] - Implement beginning of a new epoch

[lukaszrzasik]

What is this task and why do we need to work on it?

These changes should focus on behaviour of the nodes in the next epoch, i.e. voting for the last block in the previous epoch, proposing the first block in the new epoch and voting for the first block in the new epoch.

The details of the algorithm can be found here: https://www.notion.so/espressosys/Epoch-transition-without-extra-types-and-with-last-votes-broadcast-1112431b68e98092a47aea71b41bec8c

What work will need to be done to complete this task?

No response

Are there any other details to include?

No response

What are the acceptance criteria to close this issue?

The nodes in the next epoch correctly vote for the last block in the previous epoch and for the first block in the new epoch.

Branch work will be merged to (if not the default branch)

No response