Feature/provider config (#570)

New Features
- Automatic provider failover & rotation across multiple provider URLs with a provider:// scheme and capped retries
- Configurable failover redirect patterns to influence retry/failover behavior
UI

- New interface to view and edit failover redirect patterns in reverse proxy configuration

- Expanded docs covering Provider Failover & Rotation and enriched messaging templating
Reliability

- Improved URL resolution, error reporting and logging for more robust provider handling

backend/src/api/endpoints/v1_api.rs

@@ -85,6 +85,7 @@ async fn geoip_update(axum::extract::State(app_state): axum::extract::State<Arc<
             let input_source =  InputSource {
                 name: "GeoIP".intern(),
                 url,
+                provider: None,
                 username: None,
                 password: None,
                 method: InputFetchMethod::GET,