[1.5.x] Made gis get_default_columns mirror changes in normal compiler

The copy-pasted part of gis compiler's get_default_columns wasn't
changed to match changes in a0155f35343afbfd9e98ab9aa4615f06780f697e.
[1.5.x] Added further flexibility to ModelAdmin for controlling post-save redirections.
Refs #19505.
Backport of cee40c7d79930ff42bde4
[1.5.x] Fixed #19537 -- Made CheckboxInput._has_changed handle 'False' string

Thanks dibrovsd@gmail.com for the report.
Backport of d11038acb2 from master.
[1.5.x] Fixed #16241 -- Ensured the WSGI iterable's close() is always called.

Thanks Graham Dumpleton for the report.

Backport of a53c474.
[1.5.x] Fixed #19519 -- Fired request_finished in the WSGI iterable's close().

Backport of acc5396.
[1.5.x] Fixed #19453 -- Ensured that the decorated function's arguments are obfuscated in the @sensitive_variables decorator's frame, in case the variables associated with those arguments were meant to be obfuscated from the decorated function's frame.
Thanks to vzima for the report.
Backport of 9180146d21cf2a31eec
[1.5.x] Fixed #19519 again -- Regression in LiveServerTestCase after fd1279a4.

Backport of 328f5b5.
[1.5.x] Updated translation catalogs for core and admin
[1.5.x] Added a helper script for managing django translations

Backport of 739724ff82 from master.
[1.5.x] Removed unusable parameters to empty_form property

Backport of 884f77bd1 from master.
[1.5.X] Fixed #19520 - Corrected some misleading docs about template_name_suffix.

Thanks jnns for the report.

Backport of 0d3f16b12e from master
[1.5.X] Fixed #19549 - Typo in docs/topics/auth/default.txt

Backport of 695b2089e7 from master
[1.5.x] Fixed #19547 -- Caching of related instances.

When &'ing or |'ing querysets, wrong values could be cached, and crashes
could happen.

Thanks Marc Tamlyn for figuring out the problem and writing the patch.

Backport of 07fbc6a.
[1.5.x] Minor fixes in the known_related_objects tests.

* Fixed JSON indentation.
* Avoided relying on implicit ordering.

Backport of a7b7efe.
[1.5.x] Update doc example for overriding change_form.html

Slightly reworded another related paragraph for clarity, too.

Backport of 3f890f8.
[1.5.x] Fixed #19516 - Fixed remaining broken links.

Added -n to sphinx builds to catch issues going forward.

Backport of 9b5f64cc6e from master.
[1.5.x] Fixed #19545 -- Make sure media/is_multipart work with empty formsets

Backport of 3fc43c964e from master.
Fixed #19426 -- Adapted EmptyQuerySet.distinct signature

1.5-only change, as EmptyQuerySet will be refactored in 1.6.
Thanks hongshuning@gmail.com for the patch.
[1.5.x] Fixed #19134 -- Allowed closing smtp backend when the server is stopped

Thanks Sebastian Noack for the report and the initial patch.
Backport of 1b3f832ab7 from master.
[1.5.x] Fixed #19382 -- Stopped smtp backend raising exception when already closed

Thanks Sebastian Noack for the report and the initial patch.
Backport of ffa50ca35 from master.