This patch adds a new parameter ``--host`` to
``openstack server unshelve`` command. This can help administrators to specify
an ``host`` to unshelve a shelve offloaded server.
And add new parameter ``--no-availability-zone`` to unpin a server availability
These parameters are available in the 2.91 microversion.
Depends-On: https://review.opendev.org/c/openstack/python-novaclient/+/831651
Implements: blueprint unshelve-to-host
Change-Id: I7986adc7563f63bcd4b3caf5eb7bc4329b4e1eca