Order actions sensibly within Differential revision comment action groups

Summary:
Ref T11114. See D17114 for some discussion.

For review actions: accept, reject, resign.

For revision actions, order is basically least-severe to most-severe action pairs: plan changes, request review, close, reopen, abandon, reclaim, commandeer.

Test Plan: Viewed revisions as an author and a reviewer, saw sensible action order within action groups.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T11114

Differential Revision: https://secure.phabricator.com/D17115