added integration tests with molecule testinfra

[mkayontour]

Added integration tests with testinfra. In the folder molecule there are tests/integration with testinfra scripts.

It's simple to use just define the modules in a def and write the assert statements.
https://testinfra.readthedocs.io/en/latest/modules.html
https://testinfra.readthedocs.io/en/latest/

Example:

def test_icinga2_service(host):
    service = host.service("icinga2")
    assert service.is_running
    assert service.is_enabled

Every python script in this directory will be used and verified.