Add lint warnings about use of phutil_render_tag and javelin_render_tag

Summary: Raise deprecation warnings for these methods. I won't commit this until the phutil_tag branch merges.

Test Plan: Unit tests.

Reviewers: vrana

Reviewed By: vrana

CC: aran

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4770