Fixed #24002 -- GenericRelation filtering targets related model's pk

Previously Publisher.objects.filter(book=val) would target
book.object_id if book is a GenericRelation. This is inconsistent to
filtering over reverse foreign key relations, where the target is the
related model's primary key.
Fixed display of lists after website redesign

Thanks Brian Jacobel for the report. refs django/djangoproject.com#197
Fixed #23497 -- Made admin system checks run for custom AdminSites.
Removed netCDF from GIS driver testing; refs #23804.

It may not be installed on all systems.
Fixed #24007 -- Ensure apps registry's ready before unpickling models

This prevents AppRegistryNotReady errors when unpickling Django
models from an external script.
Updated TemplateResponseMixin docs to reflect new behavior after refs #23789.
Allowed Python executable names other than python in test from refs #24007.
Fixed #24014 -- Unified OGRException and GDALException

Thanks Tim Graham for the review.
Refs #24020 -- return expressions from get_group_by_cols()
Fixed #23788 (2) -- Improved gettext version checker

Thanks Tim Graham for the report and initial patch.
Removed need to update Python version support note on each new release.
Forward-ported test and release note from f46a16614

Refs #24015.
Moved version directives to the bottom of the loaddata section.
Used the :ticket: syntax more extensively
Used https for most *.python.org links
Updated some other external links in the docs
Made model_regress unpickling test CWD-independent

Refs #24007. Thanks Tim Graham for his help with the patch.
Fixed refs #24007 test on Windows.
Added words to docs wordlist.
Added upgrade instructions for deprecated model _meta permission methods.