net-mgmt/netbox: Create Django 4.0 consumers

• Django 3.2 is currently the "default" version in the ports tree due its long term support until April 2024. Thus ports that are assigned to that version will exist until then.
  
  The following ports are required to make the upgrade of net-mgmt/netbox to the 3.2 release possible because it requires Django 4.0.
  
  All of the ports listed below were created on the basis of their respective original ports:
  • devel/py-dj40-django-rq
  • devel/py-dj40-graphene-django
  • www/py-dj40-django-auth-ldap
  • www/py-dj40-django-cors-headers
  • www/py-dj40-django-debug-toolbar
  • www/py-dj40-django-filter
  • www/py-dj40-django-graphiql-debug-toolbar
  • www/py-dj40-django-js-asset
  • www/py-dj40-django-mptt
  • www/py-dj40-django-prometheus
  • www/py-dj40-django-redis
  • www/py-dj40-django-tables2
  • www/py-dj40-django-taggit
  • www/py-dj40-django-timezone-field
  • www/py-dj40-djangorestframework
  • www/py-dj40-drf-yasg

• Simplify the related CONFLICTS_INSTALL entries as well. This also reduces editing of the Makefiles if another ports need to be "repo-copied" (e.g. for Django 4.1) based on the original ports in the future. [1]

Reviewed by: se [1], sunpoet
Differential Revision: https://reviews.freebsd.org/D35444