AccessControl unification discussion

[TrejGun]

🧐 Motivation

As we now have #4425 I would like to raise the question about the unification of AccessControlDefaultAdminRules and Ownable2Step

These two flows look very similar but have slightly different implementation

Ownable2Step	AccessControlDefaultAdminRules
pendingOwner	pendingDefaultAdmin
N/A	pendingDefaultAdminDelay
N/A	defaultAdminDelayIncreaseWait
N/A	changeDefaultAdminDelay
N/A	rollbackDefaultAdminDelay
transferOwnership	beginDefaultAdminTransfer
acceptOwnership	acceptDefaultAdminTransfer
N/A	cancelDefaultAdminTransfer

I want to propose to unify them

[TrejGun]

@Amxx this would be really nice if you had a chance to look at this ticket and tell your opinion, because this is a breaking change and it would be amazing to have a unified interface in v5, especially looking at the changes you are doing with the vesting wallet