[New feature] Logging external network connections

[frisso]

VMs running on clusters may have full Internet access. This may pose non trivial security risks, as traffic is NATted and hence it may not be possible to discover to the originating VMs in case of malicious actions are carried out on the Internet.
This feature request proposes the creation of a "per-session logger", per-VM, which is able to save a record containing the most important information associated to each TCP connection established from the VM to the outside world.