Allowlist proposal creators

[NoahSaso]

Right now, the pre-propose modules allow the DAO to decide between anyone can propose or only members can propose. We should add a third option that lets the DAO specify exactly who can make proposals, which enables many other use cases.

Maybe a DAO wants community members to vote but not create proposals, and a parent DAO or operations SubDAO is responsible for making proposals.

Or maybe a contract in a protocol makes proposals for the team to allow or reject automated actions.