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

backend/app/api/v1/datasources.py

@@ -99,8 +99,22 @@ COLLECTOR_INFO = {
         "priority": "P1",
         "frequency_hours": 168,
     },
-    "fao_landing_points": {
+    "arcgis_landing_points": {
         "id": 16,
+        "name": "ArcGIS Landing Points",
+        "module": "L2",
+        "priority": "P1",
+        "frequency_hours": 168,
+    },
+    "arcgis_cable_landing_relation": {
+        "id": 17,
+        "name": "ArcGIS Cable-Landing Relations",
+        "module": "L2",
+        "priority": "P1",
+        "frequency_hours": 168,
+    },
+    "fao_landing_points": {
+        "id": 18,
         "name": "FAO Landing Points",
         "module": "L2",
         "priority": "P1",