Use "CommentPro" controller instead of "Comment" controller

Summary: Ref T2222. This will probabaly have a few rough edges too, but seems to work well.

Test Plan:

• Made a bunch of comments while building this.
• Made some new comments.
• Verified that the Asana/JIRA integration is only a little bit janky, not completely broken.

Reviewers: btrahan

Reviewed By: btrahan

CC: aran

Maniphest Tasks: T2222

Differential Revision: https://secure.phabricator.com/D8362