Use fuzzy search when usual search fails

This PR extends the existing search in that when the existing search does not find any results, it will use the newly created fuzzy indices (soundex and metaphon indices). This fixes most typo-driven errors.

@davidoesch @cedricmoullet @ltclm
[Test here](http://mf-geoadmin3.dev.bgdi.ch/gjn_soundex) and compare with current production.

Note: only the `locations` search is affected and only addresses have fuzzy indices right now (not plz, cantons, municipals and other elements of swisssearch)