4380: Node Manager SLURM dispatcher proceeds from more states.

Per discussion with Ward.  Our main concern is that Node Manager
shouldn't shut down nodes that are doing work.  We feel comfortable
broadening the definition of "not doing work" to this set of states.
4293: Node Manager shuts down nodes that fail to boot.

This helps Node Manager detect and correct when a node fails to
bootstrap.
Merge branch '4293-node-manager-timed-bootstrap-wip'

Closes #4293, #4732.  Refs #4380.