hgweb: pass modern request type into various webutil functions (API) Our march towards killing wsgirequest continues. .. api:: Various functions in hgweb.webutil now take a modern request object instead of ``wsgirequest``. Differential Revision: https://phab.mercurial-scm.org/D2802

hgweb: don't redundantly pass templater with requestcontext (API) The requestcontenxt has a ``tmpl`` attribute to access the templater. We don't need to pass the templater explicitly when passing a requestcontext instance. .. api:: Various helper functions in hgweb.webutil no longer accept a templater instance. Access the templater through the ``web`` argument instead. Differential Revision: https://phab.mercurial-scm.org/D2801