R1:06aa207960bc

Allow users to have profile icons

Summary: Ref T10054. This primarily improves aesthetics and consistency for member/wathcher lists in projects.

Test Plan:
{F1068873}

{F1068874}

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T10054

Differential Revision: https://secure.phabricator.com/D15103