Per deprecation timeline.

Per deprecation timeline.

Refs #9893 -- Removed shims for lack of max_length support in file storage per deprecation timeline.

Per deprecation timeline.

Per deprecation timeline.

When someone needs to build a custom backend-specific GIS lookup, it
is much easier done if getting the spatial operator class happens in
a dedicated method (no need to rewrite the entire as_sql() method).

Without an explicit 'level', only messages at WARNING or higher
are handled. This makes the config consistent with the docs
which say, "The django catch-all logger sends all messages at
the INFO level or higher to the console."

Reverted "Fixes #24727 -- Prevented ClearableFileInput from masking
exceptions on Python 2" and added a regression test.

This reverts commit 5c412dd8.