Governor: Use smaller integers for timing parameters

[cygnusv]

Some voting timing parameters are expressed as uint256, like votingDelay and votingPeriod inGovernorSettings, while the newly introduce GovernorPreventLateQuorum has a votingExtension parameter with type uint64. These should be consistent.

[Amxx]

Hello @cygnusv, and thank you for raising that issue.

I'll check what we can do, but please note that we want to move the votingDelay and votingPeriod to uint64

[cygnusv]

Right, either way works 👍

[AtlasPilotPuppy]

fixed in #3224

[frangio]

Sorry folks the getters that return uint256 were inherited from GovernorBravo and we defined them that way for compatibility with that contract. That hasn't changed so I think we should keep them this way.

[frangio]

Following up on my previous comment. While the external getters should continue to return uint256, we can change the storage variables to use uint64 in order to more efficiently pack storage.

This is a breaking change that would be scheduled for 5.0.