SPv4 - Management network not used

[bewing]

VIRL files do not have place holders for management interfaces, nor set the mgmt_ip extension that instructs VIRL to console in and manually set the management IP of the device. This also allows one to monitor the management reachability of a node via the VM Maestro simulation screen.

Additionally, configuration templates should allow telnet on the management interfaces where possible.

I'd be happy to submit a pull request with modified .virl files, as my preferred workflow is a tmux session on the LXC host instead of utilizing console ports.