TablePager: Modernize style loading
* Create a CSS module for pager styling (table and navigation),
pulling in existing styles for shared.css. Load it on all pages
where the pager itself is shown.
* Build a ParserOutput object encapsulating the return HTML and
required modules, rather than only providing the HTML. Added some
hacks for backwards-compatibility with old-style calls and
soft-deprecated them (there are many usages in extensions).
Other cleanup:
* Remove styles in oldshared.css, they were all overwritten by
shared.css or by styles for .mw-datatable.
* Remove inline styles where possible, explain them where impossible.
* On SpecialListFiles, display navigation bar above the table as well
as below (this seems to be the convention for other pages).
Change-Id: Iae976f854b96b5c61691918787c4dff7db089c28