I’d like to submit a PR to add three fields to servers.ListOpts: ip, ip6, and user_id.

Documentation: https://docs.openstack.org/api-guide/compute/server_concepts.html#server-query
Source: https://github.com/openstack/nova/blob/a948a803b561606a892133940915caae610c080b/nova/api/openstack/compute/schemas/servers.py#L567