ABCI++: Synchronize ExtendVote and VerifyVoteExtension spec and implementation

[sergio-mena]

Summary

Synchronize ABCI++ interface APIs ExtendVote and VerifyVoteExtension in spec repo (v0.36 branch) with those in abci++ branch of the Tendermint Go repo.

Problem Definition

Once the protobufs are synchronized, we need to adapt the code in the consensus logic.

This issue depends on #7664 because we need to decide when to carry out this implementation.
If, in the end, it will land in 0.37, then we need to back out all VoteExension related PRs in the abci++ branch for v0.36

Dependencies

• Update abci++ branch to master #7653
• abci: update proto's to reflect changes in ABCI++  spec#386
• ABCI++: Decide how to handle vote extension in the block format #7664

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