Fixed #22682 -- `makemigrations` will create `MIGRATION_MODULES` package

`makemigrations` will automatically create the package specified
in `MIGRATION_MODULES` if it doesn't already exist.

Thanks ovidiuc4 for the report.
Merge pull request #2744 from mmardini/MIGRATION_MODULES

Fixed #22682 -- `makemigrations` will create `MIGRATION_MODULES` package