[1.7.x] Fixed #22979 -- Moved bug* tests

Backport of 11181a64f from master.
[1.7.x] Only warn about initial data if fixtures have been found.

Backport of 2ab0ed7b2842fbb8bf36ee7df9949d10546d953d from master.
[1.7.x] Fixed #23098 -- Checked that lazy choices are not evaluated too soon

Thanks Matthieu Agopian for the report.

Backport of 2f73b527dda6683868fac2791f7f07ccb01ea0d9 from master.
[1.7.x]  Update from key ID in security.txt to authorized release keys list.

Backport of fe87f8d6707e13fb9416d8e4c1ebc01817d53755 from master.
[1.7.x] Bump version number for 1.7 RC 2.
[1.7.x] Fixed #23062 -- Documented how to create superuser.

Patch by Tim Graham. Thanks areski for the review.

Backport of 53a61d8 from master.