[feature request] Add number of matchs in labels

[erdnaxe]

Currently Tulip adds a FLAG label on a flow when the flag regex has one or more match.
It would be useful to store how many times the regex matched the TCP data, then display it like FLAG x3.

This could be useful to spot unusual amount of flags in a TCP flow.

[devgianlu]

We had this feature on the TeamItaly fork, I'll make a PR in the next weeks.