Use Tempest-lib's compute baremetal_nodes_client

Compute baremetal_nodes_client has been migrated to tempest-lib-
I528505bdd0a51cf720578dc6c5ef4301b72b5ce0

Now Tempest-lib provides this client as stable interface so Tempest
should start using this from lib and remove its own copy.
Also remove other files for this client like response schema, unit tests.

This commits makes Tempest to use compute baremetal_nodes_client
from Tempest-lib.

Change-Id: I2bcfcb9df21d3dfa3c0f511f46006032c0ea632b
4 files changed