New automount map management module.

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

    plugins/modules/ipaautomountmap.py

The server module allows to ensure presence and absence of automount
maps. The module requires an existing automount location to place the
map within. It does not create any automount keys with in the map.

Here is the documentation for the module:

    README-automountmap.md

New example playbooks have been added:

    playbooks/automount/automount-map-absent.yaml
    playbooks/automount/automount-map-present.yaml

New tests for the module:

    tests/automount/test_automountmap.yml