Rudder tools

This scenario will setup a vm from a json file in platforms, install rudder-agent/rudder-server-root on it following its configuration and then install a given version
of ncf from the git repository, install it and execute the ncf tests from it.
The vm should be destroyed afterward.

There are some new functions to execute remote command on the different hosts since some command execution can be very long (tests) and we want to have a direct feed-back on the output
to make debugging easier.

We should also start to think about splitting the main rtf file in some smaller ones. This will not be super clear since the code parts are not completely independent, but at least,
reading 3 files of 500 lines is easier than 1 big one of 1500.