Summary: Ref T10319. This swaps the default in the Picture Chooser to allow picking of the custom unique avatar. We're currently going with 100k unique possibilities. The logic roughly hashes a user name and picks an image pack, color, and border. Based on that, we select the first character of their username, or fall back to Psyduck if not [a-z][0-9].
Test Plan:
Set the following usernames from ProfilePicture as a test: chad, epriestley, sally, 007, _cat_, -doggie-.
{F3453979}
Reviewers: epriestley
Reviewed By: epriestley
Subscribers: Korvin
Maniphest Tasks: T10319
Differential Revision: https://secure.phabricator.com/D17430
