Node spams with error logs when self-terminates because of insufficient storage

[alexggh]

When node self-terminates because of insufficient with

main storage-monitor: Available space 828MiB for path `/chain-data/chains/versi-networking/db/full` dropped below threshold: 1024MiB , terminating... 

Then it starts spam the logs with around 900K lines of logs, this puts a strain on our logging framework, so we should try to avoid it if possible.

netlink_proto::connection: netlink socket stream shut down
 libp2p_mdns::behaviour: if watch returned an error: rtnetlink socket closed  
 error flushing netlink socket: Custom { kind: Other, error: "A Tokio 1.x context was found, but it is being shutdown.

https://grafana.teleport.parity.io/goto/uWFcFOfSR?orgId=1

Note! This is not a flow that normal validators would exercise, so it is just nice to have fix, if it can be done with low effort.

[BulatSaif]

A Tokio 1.x context was found

This error not always caused by insufficient space. Usually, the node just exits with an error if you have insufficient space.

I've encountered it several times by simply killing the node with "Ctrl+C" on startup (enough disk space). This error blocks the terminal, requiring you to log in with a second terminal to kill the process.

[sandreim]

What we need is graceful node shutdown for such situations.