The HTTP request body contains the node ID where the request should
be routed and without decoding this, we cannot route to anything
other than local nodes.
The Nomad clients store their Nomad identity in memory and within
their state store. While active, it is not possible to dump the
state to view the stored identity token, so having a way to view
the current claims while running aids debugging and operations.
This change adds a client identity workflow, allowing operators
to view the current claims of the nodes identity. It does not
return any of the signing key material.
