add DSCP/ToS flag in bridge mode

[syadnom]

I (and many others) would like to put ntopng in front of our networks to identify and mark traffic types so that those marks can be used in our firewall and traffic shapers

For example:
ntopng as 'bump in wire' on the wan side of a traffic shaper.
ntopng marks bittorrent with a DSCP/ToS tag.
In the traffic shaper, mark connections with the bittorrent DSCP tag so that those connections can be shaped.

another example:
same physical layout, but this time identify windows update and mark with a different DSCP tag.
Router can now route those packets (via identifying the DSCP tag) through a windows update proxy.

[kong156]

this would be nice, indeed!

[lucaderi]

As we now have ntopng in inline mode, this feature is no longer necessary as internally ntopng can block/shape traffic natively.