Django-rubble

Refactor

- **functions**: simplification of some number functions to better utilize Decimal methods

Fix

- **django-version**: previous change didn't allow django >5.0 :clown_face:

Refactor

- **rename-package**: from django-utils (already taken) to django-rubble

Feat

- **percentage_field**: add percentage field as model field with form field and Percent type

Fix

- **django-version**: was ~5.0 which doesn't work with 4.x versions... changed to <=5.0