Compute servers are able to be queried/listed by Availability Zones. This support should be added.

This ability has been available since the base 2.1 API version, though it was restricted to only admins. However, that has no bearing on the Gophercloud implementation.

https://github.com/openstack/nova/blob/50fdbc752a9ca9c31488140ef2997ed59d861a41/nova/api/openstack/compute/schemas/servers.py#L593