Since it is sometimes hard to get a comprehensive view of the flows given having to choose a reporter - or too noisy when selecting "both" reporters - this story aims to provide a new option to merge ingress and egress reporters.

Along with NETOBSERV-1025, this will solve some of the issues mentioned in NETOBSERV-697, which was closed (won't fix) as a bug but to be replaced with these stories

EDIT: throughout this PR I ended up removing entirely the "reporter" option, traded for a simpler approach of showing always "both" reports but with hidden duplicates (merged) - and only keeping as an option to show duplicates.
It seems much simpler to reason about, and allows to remove some of the UX load. Users wanting to filter specifically ingress/egress can still do it via the regular filters.