plugins

There was state: rebuild before, but the code was incomplete and was not
able to run properly.

New parameters:
- users: Limit the rebuild to the given users only
- hosts: Limit the rebuild to the given hosts only
- no_wait: Don't wait for rebuilding membership

New parameters and examples have been added to README-automember.md

tests/automember/test_automember_client_context.yml has been using
state: rebuild and lacked the automember_type parameter.

grouping was used in functions and has been replaced by automember_type.

Some typos in examples have been fixed also.

New playbooks:
- playbooks/automember/automember-group-membership-all-users-rebuilt.yml
- playbooks/automember/automember-group-membership-users-rebuilt.yml
- playbooks/automember/automember-hostgroup-membership-all-hosts-rebuilt.yml
- playbooks/automember/automember-hostgroup-membership-hosts-rebuilt.yml

New tests:
- tests/automember/test_automember_rebuilt.yml