Implement `unverify` class of commands

[ankith26]

Description

There are three modes of unverify I'd like to implement, based on who's running it.

Any user must be able to unverify themselves in a server (should remove access roles). In addition to this any user must be able to remove their own record from the DB.
A server moderator/admin must be able to unverify any member of the server for moderation purposes. In doing so, there must be a way that this is automatically messaged to the bot admins, so that they can decide on whether to remove the corresponding record from the db.
A bot admin must be able to unverify (remove the record from the DB) any user.

Tasks

TODO