Rework !verify-admin to allow single call for both toggle and description #328

The current implementation of !verify-admin is unwieldy and requires two calls to verify a user and set their description. Lets take the difficulty out of that

Possible approaches:

• Toggle on each call
  • This falls over if we just want to change someone's role
• Use flag (i.e. !verify-admin -v Message)
• Use a flag or other indicator and contain Message in quotation marks
• ... I'm not going to give you all the ideas :)