Review Mozilla 1856029: Enable GPC Setting in Beta and Release

Bugzilla: https://bugzilla.mozilla.org/show_bug.cgi?id=1856029

Added an option to enable sending Global Privacy Control (GPC) headers. One of the comments mentioned it is sent by default in private browsing mode, but I'm not sure.

Obviously a server could do nothing with the extra header, or it may depend on the jurisdiction of your tor exit node (every tor user is a temporary resident, haha), but supposedly this will have more legal enforcement behind it than DNT (Do Not Track) did. So I wonder if this might improve the browsing experience for the websites that do respond to it. E.g. do we get less cookie popups, or less traffic?

Might want to combine it with DNT to make it consistent.