[new] net/py-libknot - python bindings for knot DNS

Hi,
I've attached a port for py-libknot which allows
a much better control for knot through scripting rather
than parsing the knotc(8) output. Plus this is
maintained by the knot team and in the same repository
as knot so it should be (and imo is) pretty stable.

Port made with `portgen py libknot`.

Best,
Aisha