feat(instance): make the status page URL configurable (#1159)

fluxer_admin/src/routes/system_actions.rs

@@ -683,6 +683,8 @@ fn build_app_public_update(form: &MultiValueForm) -> InstanceConfigUpdateRequest
                 wordmark_url: optional("app_wordmark_url"),
                 favicon_url: optional("app_favicon_url"),
                 theme_color: optional("app_theme_color"),
+                status_page_url: optional("app_status_page_url"),
+                status_page_incident_history_url: optional("app_status_page_incident_history_url"),
             }),
             setup: Some(AppSetupConfigUpdateRequest {
                 configured: Some(form.bool_value("app_setup_configured")),