Send GNS3 VM settings from the GUI to the controller

[julien-duponchelle]

No description provided.

[julien-duponchelle]

I have implement the settings. For the moment it's just send and save on the controller.

I have change the save of the settings to use the gns3_controller.conf in order to have a single file for all stuff manage by the controller.

In order to simplify I have move the settings to a dedicated page:

I have also extend you concept of engines and return the list from the API. So if someone want to make an engine for a cloud provider, hyper-v or something else you should have no impact on the GUI. Now that the GUI has no direct access to VMware or VirtualBox the code is simple.