Enforce Admin rights when creating a new hub

[pegahcarter]

It should be double-checked on contract-side to verify whether we are correctly enforcing admin rights after deploying a new hub. This may need to be checked on ĀutID.sol side as well. Maybe adding a "label" such as "Admin" vs. "Participant" for each Hub struct in ĀutID.

[pegahcarter]

Currently, HubRegistry.deployHub() is openly-callable (I've commented out Allowlist). IMO, there's no reason to guard creation of a hub- it creates additional admin overhead to create new hubs on behalf of users and restricts users from openly playing around with the protocol. Lmk your thoughts @Jabyl .