Specific exit code on helmfile timeout

[j-zimnowoda]

There are number of cases when helmfile may return non-zero exit code. Often a user can deduct from helmfile output the root cause of failure. Unfortunately that is not the case of timeout event.

Usually timeouts are caused by Pending kubernetes resources that prevent successful deployment. It would be very beneficial to have a distinct exit code for timeout, so users can leverage it and automate some steps of root cause analysis, e.g.: to print kubernetes events on helmfile timeout.