Auto-capitalize user's callsign

[norrisng]

When storing user-entered callsigns (i.e. the first thing that gets entered when the client is opened), auto-capitalize them before saving them to the database.

Ultimately, it doesn't really matter that much, as its only use is to serve as a "confirmation" for the user. It merely provides a way for a user to make sure that their verification code hasn't been used by someone else (via the status bot command).

That being said, it does look nicer.

[norrisng]

Implemented in eabfbc3.