New group management module

There is a new group management module placed in the plugins folder:

  plugins/modules/ipagroup.py

The group module allows to add, remove, enable, disable, unlock und undelete
groups.

The group module is as compatible as possible to the Ansible upstream
`ipa_group` module, but addtionally offers to add users to a group and also
to remove users from a group.

Here is the documentation for the module:

  README-group.md

New example playbooks have been added:

  playbooks/user/add-groups-to-group.yml
  playbooks/user/add-user-to-group.yml
  playbooks/user/add-group.yml
  playbooks/user/delete-group.yml

README-group.md

@@ -0,0 +1,153 @@
+Group module
+============
+
+Description
+-----------
+
+The group module allows to add, remove, enable, disable, unlock und undelete groups.
+
+The group module is as compatible as possible to the Ansible upstream `ipa_group` module, but addtionally offers to add users to a group and also to remove users from a group.
+
+
+Features
+--------
+* Group management
+
+
+Supported FreeIPA Versions
+--------------------------
+
+FreeIPA versions 4.4.0 and up are supported by the ipagroup module.
+
+
+Requirements
+------------
+
+**Controller**
+* Ansible version: 2.8+
+
+**Node**
+* Supported FreeIPA version (see above)
+
+
+Usage
+=====
+
+Example inventory file
+
+```ini
+[ipaserver]
+ipaserver.test.local
+```
+
+
+Example playbook to add groups:
+
+```yaml
+---
+- name: Playbook to handle groups
+  hosts: ipaserver
+  become: true
+
+  tasks:
+  # Create group ops with gid 1234
+  - ipagroup:
+      ipaadmin_password: MyPassword123
+      name: ops
+      gidnumber: 1234
+
+  # Create group sysops
+  - ipagroup:
+      ipaadmin_password: MyPassword123
+      name: sysops
+      user:
+      - pinky
+
+  # Create group appops
+  - ipagroup:
+      ipaadmin_password: MyPassword123
+      name: appops
+```
+
+Example playbook to add users to a group:
+
+```yaml
+---
+- name: Playbook to handle groups
+  hosts: ipaserver
+  become: true
+
+  tasks:
+  # Add user member brain to group sysops
+  - ipagroup:
+      ipaadmin_password: MyPassword123
+      name: sysops
+      action: member
+      user:
+      - brain
+```
+`action` controls if a the group or member will be handled. To add or remove members, set `action` to `member`.
+
+
+Example playbook to add group members to a group:
+
+```yaml
+---
+- name: Playbook to handle groups
+  hosts: ipaserver
+  become: true
+
+  tasks:
+  # Add group members sysops and appops to group sysops
+  - ipagroup:
+      ipaadmin_password: MyPassword123
+      name: ops
+      group:
+      - sysops
+      - appops
+```
+
+Example playbook to remove groups:
+
+```yaml
+---
+- name: Playbook to handle groups
+  hosts: ipaserver
+  become: true
+
+  tasks:
+  # Remove goups sysops, appops and ops
+  - ipagroup:
+      ipaadmin_password: MyPassword123
+      name: sysops,appops,ops
+      state: absent
+```
+
+
+Variables
+=========
+
+ipagroup
+-------
+
+Variable | Description | Required
+-------- | ----------- | --------
+`ipaadmin_principal` | The admin principal is a string and defaults to `admin` | no
+`ipaadmin_password` | The admin password is a string and is required if there is no admin ticket available on the node | no
+`name` \| `cn` | The list of group name strings. | no
+`description` | The group description string. | no
+`gid` \| `gidnumber` | The GID integer. | no
+`nonposix` | Create as a non-POSIX group. (bool) | no
+`external` | Allow adding external non-IPA members from trusted domains. (flag) | no
+`nomembers` | Suppress processing of membership attributes. (bool) | no
+`user` | List of user name strings assigned to this group. | no
+`group` | List of group name strings assigned to this group. | no
+`service` | List of service name strings assigned to this group | no
+`action` | Work on group or member level. It can be on of `member` or `group` and defaults to `group`. | no
+`state` | The state to ensure. It can be one of `present` or `absent`, defauilt: `present`. | yes
+
+
+Authors
+=======
+
+Thomas Woerner