Alternative Django 5.1 fix attempt: squashmigrations

[jorenham]

This is an alternative approach using django-squashmigrations to #1, that hopefully works for both (my) existing databases, and for new projects.

It works on my machine; does it also work on yours @astorozhevsky ?

[astorozhevsky]

@jorenham Thanks for the alternative approach! I tried it, and it works well on my end too 👍