[Bug] Expire or persist Batch Proposals

[vicsn]

🐛 Bug Report

We should make sure all validators have consistent views of Batch Proposals. As such we should either expire or persist Batch Proposals.

Steps to reproduce:

1. validator A sends Batch Proposal to validator B
2. validator A restarts
3. validator A sends a new Batch proposal to validator B
4. valdiator B disconnects from validator A with "Malicious peer - proposed another batch for the same round"

Other concerns

We should have tests in place for this, and we should also check and test whether we are expiring/persisting certificates correctly.

Your Environment

snarkOS commit: 1e445b5

[Raymond Chu]

We have an existing Issue for this https://github.com/AleoHQ/snarkOS/issues/3171