[1.7.x] Fixed migrations tests added in refs #23315.

Backport of d1299fce0e from master
[1.7.x] Fixed flake8 warnings.

Backport of 6f59d29158 from master
[1.7.x] Added release note stubs for 1.5.9 and 1.4.14.
[1.7.x] Prevented reverse() from generating URLs pointing to other hosts.

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

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

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

This is a security fix. Disclosure following shortly.
[1.7.x] Fixed #23322 -- Use resolved swappable model for dependency resolution during makemigrations

Backport of 144cff3f51 from master
[1.7.x] Bump version number for security release.
[1.7.x] Added dates to release notes.

Backport of b902be798e from master
[1.7.x] Update squashmigration docs to also mention circ dep errs (refs #23337)
[1.7.x] 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).

Backport of 56252e7 from master
[1.7.x] Fixed #23343 -- Typo in docs/ref/class-based-views/generic-date-based.txt.

Backport of 14aff0bd82 from master
[1.7.x] Fixed #23342 -- Clarified warning about naive time objects.

Thanks to apollo13 for suggested wording.

Backport of b7336ec179 from master
[1.7.x] Fixed #23324 -- Mentioned Site.id in contrib.sites docs.

Backport of a76aab3583 from master
[1.7.x] Added new supported languages
[1.7.x] Fixed #23344 -- Removed duplicate docs for file upload settings.

Backport of c7fa27d702 from master
[1.7.x] Fixed #23352 -- Added tests for MigrationGraph.{forwards,backwards}_plan

Backport of be4baaefe2 from master
[1.7.x] Fixed #23341 -- Added migration name to nonexistent migration error in makemigrations.

Backport of abd640fbdf from master
[1.7.x] Fixed #22154 -- Added "Built-in" to some class-based views titles.

Backport of 0c9f40f776 from master