Planetary body-fixed reference frame WCS description in astropy 6.0

Astropy v6.0 is going to be released by the end of this year with support for body-fixed reference frame World Coordinate System description! :champagne:

The feature has been built on top of the geodetic coordinate representation implemented in 2020 by Juan Luis Cano Rodríguez.
Also, a new bodycentric coordinate representation has been defined.
Each spheroidal body have one or multiple representations used to define a reference frame and its related WCS description.
Some examples using this new feature are available at these links.

This work was made possible thanks to EuroplanetH2024 funding via the Paris Observatory and @s.erard :pray:
A huge thank you goes to all the Astropy developers and in particular to Marten van Kerkwijk who took the time to thoroughly and patiently review the related pull requests.

Enjoy! :grinning:
And feel free to add comments or suggestions about the tutorials here or on github.

And it’s out! :fireworks: