[PRQ#49643] Deletion Request for python-castellan

MarsSeed [1] filed a deletion request for python-castellan [2]: Cleanup of unused, unmaintained OpenStack server Python module. Submitter completely MIA since 2022-11. OpenStack maintains hundreds of Python components, with frequent updates. Better drop all related abandoned packages from AUR and let people install them when needed from PyPI. [1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/python-castellan/