network.Resolver: WIP Uses AF_UNSPEC flag instead. Rename param to family.

Use of AF_INET | AF_INET6 may fail for things such as localhost.

[ci skip]
hook.py: Implements remaining script hooks.
Cleans up commented-out code.
network.Resolver: Implements IPv4/6 perference sorting.
changelog: Adds entries about HookableMixin and Resolver param change.