[SC-472] Move everything to AccessControl roles

[hexonaut]

This PR removes the onlyThis and onlyGuardian modifiers and merges them into the more general access control contract. You may be wondering why the bridge receiver was moved back to a non-default-admin role SUBMISSION_ROLE . This is because all that actions that are admin such as set the guardian, update delay, etc should only be accessible behind the delay. IE the receiver (eg. OptimismReceiver) should not be overall admin able to execute changes without the delay.

Instead queue should be specific to bridge receiver to put a message in a delay, and the default admin is the contract itself. See: _grantRole(DEFAULT_ADMIN_ROLE, address(this)); in the Executor constructor.

So in summary:

Submission role: can submit messages under a delay
Guardian role: can cancel queued messages
Default admin role: can do anything without delay including change delay, guardian role, submission role, etc.

[github-actions]

Coverage after merging SC-472-guardian-merge-into-access-control into SC-463-merge-auth-bridge will be

100.00%

Coverage Report

File	Stmts	Branches	Funcs	Lines	Uncovered Lines
src
Executor.sol	100%	100%	100%	100%