feat: configure graceful shutdown window

docs/21-container-deployment.md

@@ -53,6 +53,7 @@ docker run --rm \
   --env ORBIT_WORKFLOW_TICK_INTERVAL=1s \
   --env ORBIT_SCHEDULE_TICK_INTERVAL=1s \
   --env ORBIT_RECOVERY_TICK_INTERVAL=2s \
+  --env ORBIT_SHUTDOWN_TIMEOUT=10s \
   --env ORBIT_METRICS_ADDR=127.0.0.1:9090 \
   --publish 8080:8080 \
   registry.example/orbit:dev