ipaclient: Replace extras module with ssh, automount, firefox and nis modules

ipaclient_extras could configure several things internally according to
provided settings. These have been ssh, sshd, automount, firefox an also
nis. The ssh and sshd configuration is now plocated in ipaclient_setup_ssh,
the automount configuration in ipaclient_setup_automount, the firefox
configuration in ipaclient_setup_firefox and the nis configuration in
ipaclient_setup_nis.

The following additional settings have been added to
roles/ipaclient/defaults/main.yml to provide the same configruation options
as ipa-client-install does:

ipaclient_no_ssh: no
ipaclient_no_sshd: no
ipaclient_no_nisdomain: no
ipaclient_configure_firefox: no