review permissions for the vm

[jspaaks]

with the current (https://github.com/xenon-middleware/xenon-tutorial/releases/tag/3.0.4) notes for preparing the VM, the VM has microphone enabled, even though we don;t need it.

Similarly, making connections to the outside world is enabled. That is currently used though in the [s]ftp examples. We could consider connecting to an [s]ftp docker and disabled making connections to the outside.