Investigate switching from net.IP to netip.Addr

[antoninbas]

Go 1.18 introduced the net/netip package: https://tip.golang.org/doc/go1.18#netip

Here is a relevant statement about the new package:

The new net/netip package defines a new IP address type, Addr. Compared to the existing net.IP type, the netip.Addr type takes less memory, is immutable, and is comparable so it supports == and can be used as a map key.

netip.Prefix also replaces net.IPNet

Switching from net to net/netip may yield significant performance improvements (reduced CPU and memory usage) for consumers of the go-ipfix library, although it may break backwards-compatibility in some places (should be ok given that there is no v1 major release yet). This should be investigated and measured.

[antoninbas]

~~I can't assign myself, but~~ I'm currently looking into this