Rename most user-facing "Autoclose" strings to "Permanent Refs"

Summary:
Depends on D20422. Ref T13277. Currently, "track only", "publish", and "autoclose" are three separate ideas. I'd like to generally merge them into a more natural idea called "permanent refs".

Since "Autoclose" effectively now controls both "autoclose" and "publish", rename it.

This doesn't rename all the methods or internals, and the documentation needs an update, but it renames most of the UI-facing stuff.

(You also can only specify branches as "Permanent Refs" today, but we may let you specify tags and other arbitrary refs in the future.)

Test Plan: Grepped, poked around the UI, saw UI show "Permanent" / "Permanent Refs" more often and "Autoclose" less.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T13277

Differential Revision: https://secure.phabricator.com/D20423