Ability to set/update user profile info

[JoselleAstrid]

• Country should now be a dedicated selection field, not extracted from a free text 'location' field. And it should be possible to set no country.
• SRC has some decent examples of new fields to add, including Twitch, Twitter, and pronouns.
• Some of the old profile fields are really outdated like AIM username. We certainly don't need dedicated fields for every one of these anymore. One option is to just delete the clearly outdated fields. Another option is to save them in a single JSON field, and then display that stuff privately only to that user when they view their profile. Then they can decide whether to move that info to the usable profile fields, or just clear it.