Adds dynamic host volumes to argument autocomplete for the `volume status` and
`volume delete` commands. Adds flag autocompletion for those commands plus
`volume create`.
Ref: https://github.com/hashicorp/nomad/pull/24479
* mkdir: HostVolumePluginMkdir: just creates a directory
* example-host-volume: HostVolumePluginExternal:
plugin script that does mkfs and mount loopback
Co-authored-by: Tim Gross <tgross@hashicorp.com>
Add several validation steps in the create/register RPCs for dynamic host
volumes. We first check that submitted volumes are self-consistent (ex. max
capacity is more than min capacity), then that any updates we've made are
valid. And we validate against state: preventing claimed volumes from being
updated and preventing placement requests for nodes that don't exist.
Ref: https://github.com/hashicorp/nomad/issues/15489