Fixed #16383 -- Raised the AttributeError raised in property of an object when used in a template.

Thanks maraujop for the report and Hiroki and Tim Graham for review.
Updated timezone docs to use timezone.now()

Thanks James Cleveland for the report and Aymeric for suggesting
the solution.
Fixed #22956 -- Made PermissionManager.get_by_natural_key() use the correct database for content type lookup.
Used JsonResponse in CBV examples.

Thanks Hiroki Kiyohara and Tim Graham for the reviews.
Fixed #22808 -- Made ModelMultipleChoiceField validation more robust to invalid data types..

Thanks Mattias Lindvall for the report and inital patch.
Replaced django-admin.py with django-admin in the man page.
Fixed #21940 -- Added kwargs to contribute_to_class() of model fields..

Thanks Kronuz for the suggestion.
Renamed "committers" to "team".
Removed references to partial commit acces.
Introduced a technical board.

Extended the scope of the core team a bit (depending on your current
perspective on that scope).
Documented current roles.
Left formal decisions up to the technical board.

As the core team grows towards 50 people, it isn't reasonable to give
everyone veto rights anymore.
Adjusted 'internals' docs to the new organization.

Most of these changes are about using the correct vocabulary -- "core
team member" vs "core developer/committer" and adding internal links.
Removed references to well-known political systems.

Some cultures can't handle these words.
Merge branch 'team-organization'.

https://groups.google.com/d/msg/django-developers/8b-wxEzWO3c/Hx3Uqg9XrksJ
Fixed #23103 -- Annotated ImageField file with image and content_type attributes.

Thanks Jeremy Dunck for the suggestion and Nick Sanford for review.
Fixed typo in docs/topics/testing/tools.txt.
Fixed #23108 -- Dropped support for PostgreSQL 8.4 & PostGIS 1.3, 1.4.

Thanks Claude Paroz for the review.
Removed some PostGIS 1.4 notes in the docs (refs #23108).
Fixed #7220 -- Allowed AbstractBaseUser.last_login to be null.

Thanks veena for the suggestion and Simon Charette and Kévin Etienne for reviews.