repo cleanup

[rbeyer]

I think the following repos under the planetarypy org can be deleted:

• https://github.com/planetarypy/planetaryimage-feedstock
• https://github.com/planetarypy/pvl-feedstock
• https://github.com/planetarypy/staged-recipes

They aren't current, and are no longer needed.

[rbeyer]

Per our discussion at our most recent meeting we agreed that these could be safely deleted, and I have done so.