Update mozilla-based page. Bugs 854561, 830914, 833055.

- Change /projects/mozilla-based/ to /about/mozilla-based/.

- Redirect /projects/mozilla-based.html to /about/mozilla-based/.

- Update product links.

Localization & URL rewrite fixes.

Wrapped string in l10n blocks. Updated rewrite rule to
handle trailing slash..

Added missing localization.