Changed config to be possible on service-create time + Added LocationService

src/api/location.toit

@@ -0,0 +1,35 @@
+import system.services
+import ..location show Location GnssLocation
+
+interface LocationService:
+  static SELECTOR ::= services.ServiceSelector
+      --uuid="b833ce53-3c2c-400c-be82-6538d2409f2d"
+      --major=0
+      --minor=1
+
+  start config/Map?=null
+  static START-INDEX ::= 2000
+
+  read-location -> GnssLocation?
+  static READ-LOCATION-INDEX ::= 2001
+
+  stop
+  static STOP-INDEX ::= 2002
+
+
+class LocationServiceClient extends services.ServiceClient implements LocationService:
+  static SELECTOR ::= LocationService.SELECTOR
+  constructor selector/services.ServiceSelector=SELECTOR:
+    assert: selector.matches SELECTOR
+    super selector
+
+  start config/Map?=null:
+    invoke_ LocationService.START-INDEX config
+
+  read-location -> GnssLocation?:
+    result := invoke_ LocationService.READ-LOCATION-INDEX null
+    if not result: return null
+    return GnssLocation.deserialize result
+
+  stop:
+    invoke_ LocationService.STOP-INDEX null

src/base/cellular.toit

@@ -6,7 +6,7 @@ import log
 import net
 
 import .at as at
-import .location show GnssLocation
+import ..location show GnssLocation
 import ..state show SignalQuality
 
 RAT_LTE_M ::= 1