Repository Clean-up

[mrbazzan]

• Remove django-app-helper and replace with pytest-django
• Add dynamic badges
• Remove stale files like setup.cfg
• Add djangocms V5
• django CMS versions: 4.1, 5.0, 5.1.0alpha1, main branch
• Python 3.10 - 3.13
• Django 5.2, 6.0, main
• Add Python 3.14

[mrbazzan]

@fsbraun
Could you please add other clean-ups that needs done here?
Especially the Python/CMS/Django versions that needs to be added.