Dialer: Lookup: Remove Auskunft / PeopleLookup

* auskunft.at is for sale
* auskunft.at/search redirects to firmeninfo.at which needs
  a paid[1] account to do search
* Since Auskunft was the only PeopleLookup we had, remove that completely
* Make restoreLookupProvider restore to the default, not the first item
  and also restore that if the last selected one isn't in the list
  (which we need since we removed an item that could have been selected)

[1] https://www.firmeninfo.at/preise/privat?l=en

Change-Id: Iff8233ce5575100930e2169a16a9491c773a14bf