feat: add data sources config system and Earth API integration

- Add data_sources.yaml for configurable data source URLs
- Add data_sources.py to load config with database override support
- Add arcgis_landing_points and arcgis_cable_landing_relation collectors
- Change visualization API to query arcgis_landing_points
- Add /api/v1/datasources/configs/all endpoint
- Update Earth to fetch from API instead of static files
- Fix scheduler collector ID mappings

frontend/src/pages/Earth/Earth.tsx

@@ -1,7 +1,7 @@
 function Earth() {
   return (
     <iframe
-      src="/earth/3dearthmult.html"
+      src="/earth/index.html"
       style={{
         width: '100vw',
         height: '100vh',