[1.5.x] Fixed #19356 -- Increased session key entropy.

Backport of d913a8b from master.
[1.5.x] Fixed #19354 -- Do not assume usermodel.pk == usermodel.id

Thanks markteisman at hotmail.com for the report.
Backport of 0eeae1505 from master.
[1.5.x] Allow custom User models to use the UserAdmin's change password view.

Backport of bfdedb687abfbdf400387092762bb7081e8e8b56.
[1.5.X] Fixed #19400 - Typo in docs/topics/auth.txt

Backport of 008e625c66 from master
[1.5.x] Fixed #19349 -- Fixed re-rendering of ReadOnlyPasswordHashWidget

Thanks tim.bowden at mapforge.com.au for the report, Andreas Hug
for the patch and Anton Baklanov for the review.
Backport of a0cd6dd11 from master.
Fixed #19015 -- Removed ISO formats from localized formats.py

ISO formats are automatically appended to the list of input
formats. Kept only when it is specified in first position, as it
has a special meaning in localize_input.
Thanks Bojan Mihelac for the report.

Backport of 90d3af380 from master.
[1.5.x] Fixed #19015 -- Add ISO input formats to all formats

Backport of 349c4c37f8 from master.
[1.5.x] Fixed #19397 -- Crash on binary files in project templates.

Thanks gw 2012 at tnode com for the report.

Backport of baae4b8.
[1.5.x] Fixed #19416 -- Fixed multi-line commands in initial SQL files

Thanks Aymeric Augustin for detecting this regression.
Backport of 5fa5621f5 from master.
[1.5.x] Fixed #19318 -- Ensured that the admin's SimpleListFilter options can be displayed as selected even if the lookup's first element is not a string.
Backport of 88e17156393b
[1.5.x] Fixed #19378 -- Ensured get_success_url returns a non-lazy URL

Backport of 795ac7deda from master.
[1.5.x] Fixed the admin_filters tests for Postgres.
Backport of c196e01100b2
[1.5.x] Fixed #19391 -- Oracle specific failure in tests

The failure was caused by using None as a choice for a CharField. To
avoid Oracle's "" <-> NULL handling the field type was changed to
IntegerField.

Backpatch of 632cf32b43609f7d674c81f81f01eb9e4a059f1f
[1.5.x] Minor idiomatic and docstring edits in ar localflavor.

45f00dbb93a0e929f4320b9c652fef51655e6872 from master.
[1.5.x] Fixed #18697 -- Made values accepted for two customizable admin templates consistent.

Thanks and at cloverfastfood dot com for the report.

b64d30405a3d5468dc8c6232747d45bbeee4f7bb from master.
[1.5.x] Amended explanation of LOCALE_PATHS setting.

Thanks Daniele Procida for the patch.

37abad73d6b61031ece67d8e58612cb39326d28e from master.
[1.5.x] Fixed #19429 -- Applied linebreaksbr to read-only fields in inlines

Applied to inlines what ec9d6b1122d did for main fieldsets.
Backport of 553838a28 from master.
[1.5.x] Fixed #19367 -- Fixed saving ContentFile in filesystem storage

This was not working properly when ContentFile was initialized with
an unicode string.
Thanks Alexey Boriskin for the report and the test.

Backport of 34dcf51e06 from master.
[1.5.x] Fixed #18574 -- Make BaseFormSet.is_valid call its underlying forms' is_valid

Thanks Simon Charette for the report and the initial patch.
Backport of 66dfcc10b from master.
[1.5.x] Fixed #19444 -- Clarified IGNORABLE_404_URLS documentation

Backport of 53b879f045 from master.