ipahost was so far ignoring IP addresses when the host already existed.
This happened because host_mod is not providing functionality to do this.
Now ipaddress is a list and it is possible to ensure a host with several
IP addresses (these can be IPv4 and IPv6). Also it is possible to ensure
presence and absence of IP addresses for an exising host using action
member.

There are no IP address conclict checks as this would lead into issues with
updating an existing host that already is using a duplicate IP address for
example for round-robin (RR). Also this might lead into issues with ensuring
a new host with several IP addresses in this case. Also to ensure a list of
hosts with changing the IP address of one host to another in the list would
result in issues here.

New example playbooks have been added:

    playbooks/host/host-present-with-several-ip-addresses.yml
    playbooks/host/host-member-ipaddresses-absent.yml
    playbooks/host/host-member-ipaddresses-present.yml

A new test has been added for verification:

    tests/host/test_host_ipaddresses.yml

Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1783976
       https://bugzilla.redhat.com/show_bug.cgi?id=1783979