templates/layout: Add origins search form in right part of top navbar

Add a quick way to perform software origins search on every displayed page by adding a search form in the top navbar.

Users will be redirected to search page when submitting it.

Remove the "Beta version" Ribbon as it was overlapping the search form.

Closes #2319 (closed)

---

Migrated from D3366 (view on Phabricator)