New hbacsvcgroup (HBAC Service Group) management module

There is a new hbacsvcgroup (HBAC Service Group) management module placed
in the plugins folder:

  plugins/modules/ipahbacsvcgroup.py

The hbacsvc module allows to ensure presence and absence of HBAC Service
Groups.

Here is the documentation for the module:

  README-hbacsvcgroup.md

New example playbooks have been added:

  playbooks/hbacsvcgroup/ensure-hbacsvcgroup-absent.yml
  playbooks/hbacsvcgroup/ensure-hbacsvcgroup-member-absent.yml
  playbooks/hbacsvcgroup/ensure-hbacsvcgroup-member-present.yml
  playbooks/hbacsvcgroup/ensure-hbacsvcgroup-present.yml

New tests added for the module:

   tests/hbacsvcgroup/test_hbacsvcgroup.yml