We don't want to delete node pools that have nodes or non-terminal jobs. Add a
check in the `DeleteNodePools` RPC to check locally and in federated regions,
similar to how we check that it's safe to delete namespaces.
Upserts and deletes of node pools are forwarded to the authoritative region,
just like we do for namespaces, quotas, ACL policies, etc. Replicate node pools
from the authoritative region.
Implements the HTTP API associated with the `NodePool.ListJobs` RPC, including
the `api` package for the public API and documentation.
Update the `NodePool.ListJobs` RPC to fix the missing handling of the special
"all" pool.
