Remove undocumented createcachetable <table_name…> support

[Mike Edmunds]

The createcachetable management command used to accept one or more table_name command-line arguments. That behavior was removed from the ​documentation in 1.7 when the command was changed to iterate over all CACHES (#15888), but the ​implementation is still in place with a "Legacy behavior" comment.

Retaining the undocumented legacy behavior adds maintenance burden (e.g., in implementing features like #36830) and creates potential confusion for users who might try to run createcachetable with a CACHES alias rather than a table name.

Suggest removing support for args in createcachetable, with deprecation notices (in case there are still some scripts out there relying on the legacy behavior).

[Md. Saikat Islam]

I agree with removing the undocumented positional arguments from createcachetable. The legacy behavior appears to provide little value while adding maintenance and potential ambiguity with cache aliases. A deprecation path followed by removal seems reasonable.

[Nikita Kostenko]

I'll take this if accepted - deprecation warning for the positional table-name args, then removal in the following feature release.

[Nikita Kostenko]

I've implemented the deprecation locally (warning, test, 6.2 notes, deprecation timeline). I'll open a PR once this is accepted.

[Nikita Kostenko]

​https://github.com/django/django/pull/21952PR

[Md. Saikat Islam]

Since author closed their PR(​https://github.com/django/django/pull/21952), instead of continuing to iterate over the reviews, I would love to take this this from here.