Search modifications
Advance the work on #179 (closed) and #178.
What's missing:
- For #178: Column reordering (the sorting part is done)
- For #179 (closed): Support of experiments using a given analyzer more than once
Nevertheless, the search page is fully functional.
This merge request includes a refactoring of the DB model of the saved searches, which is needed by @samuel.gaist to refactor the corresponding web API.