Deprecate the Napster Dissector

Ettercap has a dissector for Napster enabled by default on tcp ports 7777 and 8888. Napster hasn't been relevant for around 10 years now and, as far as I can tell, Napster isn't even a thing anymore (rolled into Rhapsody?).

As such, the Napster dissector is dead code that is claiming data on two well used ports (https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers). Also, the Napster dissector generates a number of valgrind errors when Ettercap is used on Wireshark's fuzzed captures. For example:

https://www.wireshark.org/download/automated/captures/fuzz-2009-06-26-23834.pcap
https://www.wireshark.org/download/automated/captures/fuzz-2009-06-26-29078.pcap
https://www.wireshark.org/download/automated/captures/fuzz-2009-06-27-10816.pcap
etc.

Instead of maintaining this code I think it is time to deprecate it.