Fixed #8898 -- Obsoleted SplitDateTimeWidget usage with DateTimeField

Thanks Tim Graham for the review.
Fixed #21547 -- Updated GeoDjango tutorial with PostGIS 2 output

Thanks awilliams at cironline.org for the report.
Fixed #21756 -- Skipped two timezone-related tests on Windows.

Windows cannot use a time zone other than the default time zone.

Thanks manfre for the report.