[nEdge] supporto for monodirectional multicast traffic rules

[tano46]

We would like to ask for support of monodirectional multicast traffic rules to be added

[cardigliano]

In order to implement this, a second "Network Interfaces" box should be added to handle a simple 1-level multicast hierarchy

Example:
First box (Trusted Networks): interfaces A, B, C
Second box (Restricted Networks): interfaces D, E

A, B, C can see devices in (read "receive multicast messages from") A, B, C, D, E

D, E can see devices in D, E only

The box as of today:

This should be backported to stable too.

[cardigliano]

This has been implemented. Some more testing required.