[RFE] Allow multiple groups creation.

Adding an option `groups` to create multiple groups in one operation.
Adding tests (present/absent/external/nonposix) with server and
client context.
Simple example of `groups` option:
```
tasks:
- name: Ensure 2 groups are present
  ipagroup:
    ipaadmin_password: SomeADMINpassword
    groups:
    - name: group1
    - name: group2
```

Signed-off-by: Denis Karpelevich <dkarpele@redhat.com>

playbooks/user/add-group.yml

@@ -1,23 +0,0 @@
----
-- name: Playbook to handle groups
-  hosts: ipaserver
-  become: true
-
-  tasks:
-  - name: Create group ops with gid 1234
-    ipagroup:
-      ipaadmin_password: SomeADMINpassword
-      name: ops
-      gidnumber: 1234
-
-  - name: Create group sysops
-    ipagroup:
-      ipaadmin_password: SomeADMINpassword
-      name: sysops
-      user:
-      - pinky
-
-  - name: Create group appops
-    ipagroup:
-      ipaadmin_password: SomeADMINpassword
-      name: appops

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

@@ -1,13 +0,0 @@
----
-- name: Playbook to handle groups
-  hosts: ipaserver
-  become: true
-
-  tasks:
-  - name: Add group members sysops and appops to group sysops
-    ipagroup:
-      ipaadmin_password: SomeADMINpassword
-      name: ops
-      group:
-      - sysops
-      - appops

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

@@ -1,13 +0,0 @@
----
-- name: Playbook to handle groups
-  hosts: ipaserver
-  become: true
-
-  tasks:
-  - name: Add user member brain to group sysops
-    ipagroup:
-      ipaadmin_password: SomeADMINpassword
-      name: sysops
-      action: member
-      user:
-      - brain

playbooks/user/delete-group.yml

@@ -1,11 +0,0 @@
----
-- name: Playbook to handle groups
-  hosts: ipaserver
-  become: true
-
-  tasks:
-  - name: Remove goups sysops, appops and ops
-    ipagroup:
-      ipaadmin_password: SomeADMINpassword
-      name: sysops,appops,ops
-      state: absent