Updates to the search page, frontend and backend.

* Made the backend a bit more flexible. If tags search fails it falls
back on a fuzzy text match on the offer's title and summary. We'll need
to get more fancy later, but for now it's a quick and dirty hack that
works.
Made the home page search bar work.
Merge 70952622-search-functionality-and-styling to develop

[Delivers #70952622]