Unify multisig structs Member and VoterResponse

[maurolacy]

Currently we have not two but three similar structs in multisig code, Voter, Member and VoterResponse.

Unify them into a common struct (Voter sounds like a good name), even when it implies introducing an explicit dependency between fixed-multisig and flex-multisig.

[ethanfrey]

Do we still want to do this? Is it done?

[maurolacy]

This is trivial to do, but not yet done. I'll see that it's closed.

[maurolacy]

OK, what's happening with these structs is that one set is in the context of cw3 (multisig) and the other is in the context of cw4 (groups).

In particular:

• cw3::VoterResponse is identical to cw4::MemberResponse.
• cw3::VoterDetail is identical to cw4::Member.

Now, given that cw4 is a late / more recent spec, I don't think it makes sense to introduce a dependency between the older cw3 spec and the newer cw4 spec (That is, mapping the cw3 voters to cw4 members).

And, the other way around (mapping cw4 members to cw3 voters) doesn't make much sense: A voter will in general be a member (of something), but a member wouldn't necessarily be a voter.

So, I think the sanest and simplest thing to do, is closing this without any changes.

[ethanfrey]

So, I think the sanest and simplest thing to do, is closing this without any changes.

Sounds good.
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