Add redirect to HTTPS option
Summary: Rehash of D3411. In cgi/fcgi setups we have no idea if the request is HTTP or HTTPS as far as I can tell, so make this config-triggered again. Also handle @vrana's "off" case.
Test Plan: Set this flag, observed redirect to https when $_SERVER['HTTPS'] was absent.
Reviewers: nh, vrana
Reviewed By: nh
CC: aran
Differential Revision: https://secure.phabricator.com/D3420