Improve workboard "Owner" grouping, add "Author" grouping and "Title" sort

Summary:
Depends on D20277. Ref T10333.

• Put profile icons on "Group by Owner".
• Add a similar "Group by Author". Probably not terribly useful, but cheap to implement now.
• Add "Sort by Title". Very likely not terribly useful, but cheap to implement and sort of flexible?

Test Plan:

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T10333

Differential Revision: https://secure.phabricator.com/D20278