Improve signer state machine by including a miner state in the state machine messages

[jferrant]

A signer may mark a miner invalid because it has timed out, reverting to the old miner. Other signers may still see this same miner as valid because of multiple reasons. This should be conveyed to other signers. For example, it could set miner_state to Inactive which would be that it isn't marked invalid yet (due to our timeout constraints) but has yet to produce any valid block proposals OR it could be marked Active (due to having proposed a block). The inactive case would imply that the miner MAY get marked invalid with time. The second it would not. Therefore, other signers could make more informed decisions about whether to capitulate their viewpoint or wait a little longer to see if these signers mark the miner invalid for timeout reasons.

Depends on https://github.com/stacks-network/stacks-core/issues/6092