rename NonSignerStakesAndSignature fields to be more consistent

[samlaf]

Renamed the fields of NonSignerStakesAndSignature to be more consistent and added a huge comment describing how it's meant to be used above, since it was definitely the trickiest part to understand when writing an avs.

Talked to @gpsanant about this offline. This doesn't need to be merged now (since this would trickle down to a lot of needed offchain code changes), but leaving here as a suggestion, and we can merge this whenever. I personally think it would make this struct easier to understand, but I'm open to changing some of these.

Currently I followed the convention:

    Each field array can either be over signers, nonsigners, or quorums.
    We use the first word of the variable to represent what the array is over
      eg: []nonSignersPubkeysG1 -> array of nonSigners
      eg: []quorumApkG1 -> array of quorums

But we could also potentially use a per... suffix convention

nonSignersPubkeysG1 -> pubkeysG1PerNonSigners
quorumApkG1 -> apkG1PerQuorum

Tests

Some unit tests are failing, but I don't think it's related to my changes.

[ChaoticWalrus]

I missed this PR. Looks like a good change @samlaf !
@gpsanant is there a reason we didn't merge this? Seems like a positive move and it'll be much more of a pain to do after deploying things, so if we want to merge we should do it soon.

Noting here that we should migrate this PR over to the dedicated "middleware" repo if we decide to move forward with it.

[ChaoticWalrus]

Closing this out as stale; these contracts no longer live in this repo.