When deactivating a profile in libNM, we should:
* Check `NM.ActionConnection` existence
* Check `NM.ActionConnection.props.state` not DEACTIVATED
* Use signal `state-changed` of `NM.ActionConnection`.
* Only invoke `NM.Client.deactivate_connection_async()` if not
in DEACTIVATING state.
* Ignore `NM.ManagerError.CONNECTIONNOTACTIVE` error.
This patch also introduced a new class `NetworkManagerProvider`
in `module_utils/network_lsr/nm`:
* Independent from Ansible but need to use absolute import due to
limitation of ansible 2.8.
* Provide sync function wrapping async calls of libNM.
* Use stable logging method of python.
* Only load this module when provider is nm.
This patch also changed how logging is handling in
`Cmd_nm.run_action_down()` as initial step on isolate ansible log
mechanism from provider module.
By moving provider codes to `module_utils` folder, we can eventually
simplify the bloated `library/network_connections.py`.
Signed-off-by: Gris Ge <fge@redhat.com>
