Monitoring

quickstack::monitor::nagios::server.pp takes care of the nagios server side:
* Eventually a foreman hostgroup to be created   
* and/or directly use the class  
* The server could be anywhere, it doesn't have to be one of the controller  

quickstack::monitor::nagios::client::node.pp shows what to be added to any host in order to have:  
* Nagios client part installed (nrpe)   
* Nagios hostgroup to be added in Nagios server hosts configuration. This is done via external resources.  
* I have added the client class to: controller, networker and computes classes.  

Two new parameters:  
* $monitor_ip is the nagios IP address  
* $swift is the flag to install or not swift service for nagios, I believe we need to generalize it with probably more of the same kind for other openstack components.  

Puppetdb is needed for the hosts to register their hostgroups. Those are based upon openstack installed services.
Basically after all nodes have been installed then nagios server install to be executed (or re-executed, it will add new hosts) along their services. No manual intervention needed.