Feat: Generate visual data model

I've added the ability to generate images out of the data model. Check the README for details. Thanks for merging :-)

steering/settings.py

@@ -144,6 +144,7 @@ INSTALLED_APPS = (
     "rest_framework",
     "rest_framework_nested",
     "django_filters",
+    "django_extensions",
     "drf_spectacular",
     "oidc_provider",
     "corsheaders",