[core] Implement a feature to recycle a StatefulSet if inactivity is detected

[emil-jacero]

This feature should detect if the user is inactive and "recycle" the container. In practice this would require the container to report on the activity in some way.

For code-server, this is done through the /healthz endpoint.
For other containers this would be different. For example in the webtop scenario KasmVNC has inactive_user_session_timeout but that might not expose an endpoint that can be used.

Might be a good idea to look into a way to detect the inactivity via the Envoy Proxy in some way.