Improve packetfence_install__configuration variable

[nqb]

It should be possible to override only some parts of this variable in inventory in place of redefining the whole list (like in DebOps roles).

Using combine filter seems possible but I didn't find the correct balance between list and dicts

[nqb]

In place of defining all INI files in a YAML format, we could let user use following syntax:

      - name: 'switches.conf'
        template_path: '{{ playbook_dir }}/templates/switches.conf.j2'

with switches.conf.j2 a PacketFence INI files with Ansible templates.