Optimize autocomplete static files

I noticed that we were loading the static files for the autocomplete widget in the base.html template which causes the server to serve more static files than needed on most pages, so I moved that only to the templates that actually use the autocomplete widget.

I don't have time to test it though so Colin if you could just check whether it breaks something on the other pages (because I moved the extrahead block in the template a little lower). Thanks.