Nakamoto Signer[3.0] - Port v1 signer tests to v0 once end to end miner and signer communication is complete

[jferrant]

There are some tests (e.g. block_proposal, sign_after_signer_reboot, mine_2_nakamoto_reward_cycles, etc.) that are not v1 specific tests and should be ported to v0 as well. Depends on a working path between miner block proposal, signer response, miner block append in v0.