Move all comment management junk into a dropdown menu

Summary:
man I sure hate Javascript

I removed the ajax-edit and ajax-remove interactions, becuase they were prohibitively complex to get working given that the entire menu has to change too. Instead, the page just reloads. This works perfectly fine in practice.

If we want to restore these in the future, we should have the server re-render the entire transaction group or something. I think very little is lost here, though.

Test Plan:

• Took all the actions.
• Used existing dropdown menus.

Reviewers: chad, btrahan

Reviewed By: btrahan

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D8966