ipareplica/server: Enable removal from domain with undeployment

New variables have been added to ipareplica and ipaserver role to enable
the removal from the domein with the undeployment.

`ipaserver_remove_from_domain`
This enables the removal of the server from the domain additionally to the
undeployment.

`ipaserver_remove_on_server`
The value defines the server/replica in the domain that will to be used to
remove the server/replica from the domain if
`ipaserver_ignore_topology_disconnect` and `ipaserver_remove_from_domain`
are enabled. Without the need to enable
`ipaserver_ignore_topology_disconnect`, the value will be automatically
detected using the replication agreements of the server/replica.

For the replica role it is possible to use the server variables, but
also the replica versions: `ipareplica_remove_from_domain` and
`ipareplica_remove_on_server`.

The already existing parameters `ipaserver_ignore_topology_disconnect` and
`ipaserver_ignore_last_of_role` have been added to the README files for
server and replica with descriptions. The same for the replica versions
of the parameters.

The ipareplica role is not calling the `ipa-server-install` anymore, it
is instead using (including) the server role for the task.

The new module `ipaserver_get_connected_server` has been added to the
server role to be able to get a connected server using the replication
agreements. This module is only used if
`ipaserver_ignore_topology_disconnect` is not needed.