title: How to get current location or move to current location in Xamarin.Forms.Map
body: <p>Since the Map already shows the user location (with IsShowingUser) I just want to zoom to this location. Is this easily possible or do I need to get the location on every platform, since I don't find any GeoLocation object. Only the GeoCoder...
  Is this not a common usecase to zoom to users position?</p>