reimplement packet capture in machined

[smira]

gopacket library has lots of issues in the way it is implemented, and we don't need full library for packet capture, but rather need it for parsing (in talosctl).

If we rewrite packet capture to use https://github.com/gopacket/gopacket/blob/master/afpacket/afpacket.go, rewrite pcap writer to avoid importing layers, we should get rid of most of gopacket in Talos machined.

Simply dropping PacketCapture from machined API server reduces observed RSS by around 20MiB.