Change behavior when miner times out waiting for block acceptance/rejection

[obycode]

Currently, the miner has a timeout when waiting for a block to be approved or rejected. When that timeout is reached, it essentially gives up on that block and proposes a new block. This new proposal will be guaranteed to be rejected by any signers that accepted the block initially proposed, so this is not helpful. It would be better for the miner to simply re-proposed the same block, just in case that somehow helps reach a signer which did not respond to the previous proposal.

See #5847 for background discussion.

[obycode]

The scenarios where this is necessary also highlight the need to begin punishing non-responsive signers so that they are incentivized to remain responsive. This scenario is happening more often than it should.

[obycode]

Note: this also requires an update on the signer side to re-consider the block when it receives the new proposal.