Fixed migrations tests added in refs #23315.
Fixed flake8 warnings.
Added release note stubs for 1.5.9 and 1.4.14.
Prevented reverse() from generating URLs pointing to other hosts.

This is a security fix. Disclosure following shortly.
Fixed #23157 -- Removed O(n) algorithm when uploading duplicate file names.

This is a security fix. Disclosure following shortly.
Fixed #23066 -- Modified RemoteUserMiddleware to logout on REMOTE_USER change.

This is a security fix. Disclosure following shortly.
Prevented data leakage in contrib.admin via query string manipulation.

This is a security fix. Disclosure following shortly.
Fixed #23322 -- Use resolved swappable model for dependency resolution during makemigrations
Added dates to release notes.
Fixed schema test for Oracle 11.2.0.1 which is used in Django Project's CI.

Refs #23073 Workaround.

Refs #22738 Repeats the mysql "offense". When the issue is solved, the
Oracle special case should be made to play with the solution (that is,
Oracle should be fixed the same way that mysql and the 3rd-party backneds
are).
Update squashmigration docs to also mention circ dep errs (refs #23337)
Added docstring forgotten in 56252e7.
Fixed #23343 -- Typo in docs/ref/class-based-views/generic-date-based.txt.
Fixed #23342 -- Clarified warning about naive time objects.

Thanks to apollo13 for suggested wording.
Fixed #23324 -- Mentioned Site.id in contrib.sites docs.
Fixed #23327 -- Added 'zero' syntax to migrate help message
Fixed #23167 -- Added BaseForm.__repr__()

Thanks Keryn Knight for the idea.
Tweaked docstrings from previous commit.
Fixed #23333 -- Made urlsafe_base64_decode() return proper type on Python 3.
Added new supported languages

Forward port of 46393980cf from stable/1.7.x