drain option configuable

[walf443]

When I upgrade k0s cluster, I got sometimes failure to upgrade node have some Statefulset that has long time to migrate. And I'd like to drain gracefully a Pod it's terminationGracePeriodSeconds over 120.

I'd like to configure this settings by config. (not cli option)

apiVersion: k0sctl.k0sproject.io/v1beta1
kind: cluster
spec:
  upgrade:
    drainGracePeriod: -1
    drainTimeout: 0