connlib: replace `domain` library with `hickory-proto`

[thomaseizinger]

The goal is to reduce the number of libraries we depend on and avoid conversions between different types. hickory-proto does not have an API that parses a DNS message without copying so we need to be careful to not copy every packet as DNS is the first thing we look at in every packet.

We only support DNS requests over UDP on port 53 so that should be enough to handle this without parsing.