WebSession: request info preferable in user info

* Changes the order of dictionaries in UserInfo MultiDict in favour of
  current request information e.g. `uri`.

* Fixes typos in webstyle template and cleans urlutils.
WebSearch: loadable facets

* Introduces posibility to define own facets for websearch. All facets
  are loaded from `/invenio/websearch_facets/` using pluginutils.