[1.7.x] Fixed #22337: FileSystemStorage marked as deconstructible and tested.
[1.7.x] Fixed #22576: Ensure makemigrations doesn't touch the database.
[1.7.x] Improve docs around deconstruction/serialisation (refs #22337)
[1.7.x] Bump DatabaseCreation deprecation to 2.0 (refs #22340)

Backport of 61da5f3f02 from master
[1.7.x] Fixed some markup problems in docs/releases/security.txt.
[1.7.x] Updated some docs for the delayed deprecation of legacy table creation; refs #22340.

Backport of a2e3c96948 from master
[1.7.x] Fixed #22563: Better error message when trying to change AUTH_USER_MODEL

You're not allowed to do this after you've made migrations; see ticket
for more details.
[1.7.x] Fixed #22581: Pass default values for schema through get_db_prep_save()
[1.7.x] Fixed #22496: Data migrations get transactions again!
[1.7.x] Restored site header text in password reset view.

It's the one shown when the optional integration described in
https://docs.djangoproject.com/en/dev/ref/contrib/admin/#adding-a-password-reset-feature
is used.

Follow-up to commits 6f470650d0 and 1d42a86ec7, together they fix
different small UI regressions after a962286b74.

Refs #21293.

5ea34f3f86 from master.
Made explicit lack of microsecond handling by built-in datetime fields.
Used that explicitness to appropriately nix microsecond values in bound fields.
Fixed Django ticket 22502.