Add all vehicle states to schema

Author: schnuerle

schema/templates/provider/vehicles.json

@@ -60,13 +60,17 @@
             "last_vehicle_state": {
               "enum": [
                 "available",
-                "non_operational",
-                "reserved"
+                  "elsewhere",
+                  "non_operational",
+                  "on_trip",
+                  "removed",
+                  "reserved",
+                  "unknown"
               ]
             }
           }
         }
       ]
     }
   }
-}
+}