Use the standard library `net/netip`

[mrmelon54]

Would be nice to use net/netip for IP address representation.

• net.IP would become netip.Addr
• net.IPNet would become netip.Prefix

[mdlayher]

Yep, I agree we should do this.

[mrmelon54]

I found time to debug the failing tests. My implementation should be complete now.

[mrmelon54]

Bumping this issue to see if anyone has time to look over my PR.