plugin for drain decisions

**Describe the feature**
when deciding if a node should be terminates (for example for scheduled maintainance) we want to say "don't do it now if the cluster is in trouble" by for example looking at the current node health (tainted / notread / custom node statuses) across the cluster.

**Is the feature request related to a problem?**
No

**Describe alternatives you've considered**
Built-in logic would not work since these decisions could be very custom.