feat(location): implement location search provider toggle

Add config properties for locationSearchProvider (osm/google_maps) and
googleMapsApiKey to BetterLocationConfig. Modify ChooseLocationDialog
to switch between OpenStreetMap (MAPNIK) and Google Maps tile sources
based on user preference.

- Add locationSearchProvider unique config property
- Add googleMapsApiKey string config property (SENSITIVE flag)
- Add XYTileSource for Google Maps tiles in AlertDialogs
- Pass locationSearchProvider from BetterLocationRoot to dialog

Translation keys already existed in all 28 language files.

common/src/main/kotlin/me/eternal/purrfectsnap/common/config/impl/Global.kt

@@ -28,6 +28,8 @@ class Global : ConfigContainer() {
         val spoofBatteryLevel = string("spoof_battery_level") { requireRestart(); inputCheck = { it.isEmpty() || it.toIntOrNull() in 0..100 } }
         val spoofHeadphones = boolean("spoof_headphones") { requireRestart() }
         val showBatteryLevel = boolean("show_battery_level") { requireRestart() }
+        val locationSearchProvider = unique("location_search_provider", "osm", "google_maps")
+        val googleMapsApiKey = string("google_maps_api_key") { addFlags(ConfigFlag.SENSITIVE) }
     }
 
     inner class MediaUploadQualityConfig : ConfigContainer() {