Esteemed maintainers,

Attached is an updated version of the patch.

I have removed the native-search-paths specification of PYTHONPATH. I have
also created a new output "python" that contains the python bindings. A new
phase
has been added that splits the python bindings into it's own separate
output. With that, users who only want to use gnucash programmatically can
use it with `guix environment --ad-hoc python gnucash:python`.

Please do let me know if there are any further corrections that I can make.
Thank you.