Allow reviewers to mark their own inlines as "Done" before they submit them

Summary:
Ref T13195. Ref T8573. This allows reviewers to mark their own inline comments as "Done" before they submit them.

If you're leaving a non-actionable comment like "this is good", you can pre-check "Done" to give the author a hint that you don't expect any response.

Test Plan: On revisions and commits, added inlines as the author and a reviewer/auditor. Marked them done/not-done before submitting. As author, marked the not-done ones done after submitting. Checked preivews, toggled done/not done states.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13195, T8573

Differential Revision: https://secure.phabricator.com/D19634