Generate GeoManager from GeoQuerySet. Refs #20625.

This cleanup lays the groundwork for #23533 and also addresses
the issue that GeoManager.get_queryset() failed to pass the
database router hints to the QuerySet constructor.

Thanks Anssi Kääriäinen for the review.
Fixed Oracle GIS gml() test failure introduced by e910340; refs #18757.
Fixed #23532 -- Fixed Macedonian locale date formats
Fixed #23535 -- Updated tutorial to account for default filter added in 5ea34f3f86.
Removed sudo from pip commands in docs.
Merged one_to_one_regress into the one_to_one test package.
Merged custom_columns_regress into the custom_columns test package.
Merged custom_managers_regress into the custom_managers test package.