Add PSRQpy to astroquery

I was wondering if you'd consider including my package [PSRQpy](https://psrqpy.readthedocs.io/en/latest/), used for querying the ATNF pulsar catalogue, into astroquery? If you think this is a good fit I'll get started on adding it and create a PR

One further question, if I moved it into astroquery would I still be able to easily do active development on it within astroquery?

Review astroquery's contribution and integration conventions alongside the PSRQpy documentation. The issue names no target files, tests, or entry points; first establish whether the ATNF pulsar catalogue package fits astroquery, how it would be integrated, and whether active development can continue within the repository.

Written by the indexing model from the issue text.