optimistic voting

[hxrts]

Summary

Allow governance to authorise a specific account to make proposals with constrained message type that will pass unless a quorum of token-holders vote no/no_with_veto.

Problem Definition

There are a number of maintenance operations that would be better served with an optimistic approach. As an example, let's take the proposal min deposit amount. The market just went down recently, thus the cost of making a proposal went down and a number of chains received spam proposals. A simple solution that doesn't include price feeds to fiat would be for governance to nominate an sdk group who is tasked with adjusting the min deposit. If they ever perform maliciously governance can vote no to prevent the change. Governance could also revoke the account's optimistic powers with a subsequent vote.

Proposal

This will require:

1. Addition of an optimistic gov proposal type
2. New authorization that gov can make to grant/revoke optimistic capabilities (limited to specific message types)