[cw3-flex/fixed-multisig] Status changes after voting and proposal expiration

[maurolacy]

A number of bugs were discovered in voting contracts, part of soon to be open-sourced poe-contracts. (See #12, #14, and #16).

Let's backport / adapt the fixes and tests to cw3-flex-multisig and cw3-fixed-multisig (if applicable).

[mcn8]

Would love to see this improvement

[maurolacy]

@uint will take care of this, and the follow-ups.

This involves adapting the relevant voting tests from poe-contracts, see them fail, and fix the issues.

Alternatively, this could be done by migrating the voting-contract multitests here. Now sure which is simpler. (your call, @uint)