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/services/collectors/epoch_ai.py

@@ -13,6 +13,7 @@ import httpx
 from app.services.collectors.base import BaseCollector
 
 
+
 class EpochAIGPUCollector(BaseCollector):
     name = "epoch_ai_gpu"
     priority = "P0"