Move our configure options from old-configure.in to moz.configure

"TB3: Tor Browser's official .mozconfigs." adds a --with-tor-browser-version to old-configure.in (I could not find an issue number).

However this has two problems:

1. #16439 (closed) relies on CONFIG['TOR_BROWSER_VERSION'], but a plain port of the patch to geckoview 96 did not work, so I suspect that CONFIG is not updated with items from old-configure.in
2. Mozilla is dismissing this file

So, my proposal is to move any of our changes from old-configure.in to moz.configure.