In Ibecac60d1417269bbe25a280996ca9de6e6d018f, the services in the common
role were marked as being mapped to the 'all' group, since the
'service_mapped_to_host' filter expects every service definition to have
either a 'group' or 'host_in_groups' field. While this allows the filter
to pass the common services without error, it will not actually show
them as being mapped to any hosts. This is because the filter uses the
'group_names' variable, which contains all of the groups that a host
belongs to, except the default 'all' group.

This change fixes the issue by returning True from
service_mapped_to_host when the service's group is 'all'.

Change-Id: I39c8416f5d30a535c1743f9c43434b7d2a382196
Related-Bug: #1868596

The service_mapped_to_host filter is used to check if a service is
mapped to a host, based on the group for the service or its
host_in_groups attribute if one exists. We check if the service's group
is in the 'groups' list. However, to get the list of groups to which a
host belongs, we should use the 'group_names' list.

This filter is currently only used in neutron IPv6 module loading, so
the effects are minimal.

Change-Id: I37409ca8d273b0426df0a648db222dc5432e738a
Closes-Bug: #1868285

These filters can be used to capture a lot of the logic that we
currently have in 'when' statements, about which services are enabled
for a particular host.

In order to use these filters, it is necessary to install the
kolla_ansible python module, and not just the dependencies listed in
requirements.txt. The CI test and quickstart install from source
documentation has been updated accordingly.

Ansible is not currently in OpenStack global requirements, so for unit
tests we avoid a direct dependency on Ansible and provide fakes where
necessary.

Change-Id: Ib91cac3c28e2b5a834c9746b1d2236a309529556