Delete the footer completely

Summary: Fixes T2330. Deletes the last traces of the footer.

Test Plan: Looked at several pages, saw no footer. Grepped for footer function and CSS class.

Reviewers: DeedyDas, chad

Reviewed By: chad

CC: aran

Maniphest Tasks: T2330

Differential Revision: https://secure.phabricator.com/D4554