When making a request to create a dynamic host volumes, users can pass a node
pool and constraints instead of a specific node ID.
This changeset implements a node scheduling logic by instantiating a filter by
node pool and constraint checker borrowed from the scheduler package. Because
host volumes with the same name can't land on the same host, we don't need to
support `distinct_hosts`/`distinct_property`; this would be challenging anyways
without building out a much larger node iteration mechanism to keep track of
usage across multiple hosts.
Ref: https://github.com/hashicorp/nomad/pull/24479
bbf49a9050