feat: add backup-status service (port 9999, push API for borgmatic)

compose.yaml

@@ -152,3 +152,13 @@ services:
       - '--collector.filesystem.ignored-mount-points=^/(sys|proc|dev|host|etc)($|/)'
     restart: unless-stopped
 
+  backup-status:
+    build: ./backup-status
+    container_name: backup-status
+    restart: always
+    ports:
+      - "9999:9999"
+    volumes:
+      - /app-config/backup_status_data:/data
+    networks:
+      - monitoring_network