Load module mediawiki.page.gallery.styles for all ImageGalleries
Move the added module from Parser.php to TraditionalImageGallery,
because there the gallerybox class is added to the html and at the
moment all core image galleries are extending the traditional one.
That brings the styles back for special pages like Special:NewFiles,
Special:MostImages and also on category pages with media files.
Follows Ib1aef04dc4fece78e6615386ecaef6a9f368f49e
Bug: T113511
Change-Id: I32697c2c65824d7622c1840330d6074ebb68b488