In repository settings, fold "Autoclose On/Off" into "Publishing On/Off"

Summary:
Depends on D20423. Ref T13277. Repositories currently have separate toggles for "Autoclose" and "Publishing".

Merge the "Autoclose" toggle into the "Publishing" toggle. I'm unaware of any valid use case for enabling one but not the other.

(This doesn't fix all the documentation, yet.)

Test Plan: Edited a repository, saw only one publishing option.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13277

Differential Revision: https://secure.phabricator.com/D20424