Add support for Consul Enterprise admin partitions. We added fingerprinting in
https://github.com/hashicorp/nomad/pull/19485. This PR adds a `consul.partition`
field. The expectation is that most users will create a mapping of Nomad node
pool to Consul admin partition. But we'll also create an implicit constraint for
the fingerprinted value.
Fixes: https://github.com/hashicorp/nomad/issues/13139