chore(apis_metainfo): drop unused field classes

The InheritanceForeignKey was previously used by the Uri model instead
of a foreign key. After refactoring the Uri to use a generic foreign
key, this can be dropped.

apis_core/apis_metainfo/migrations/0001_initial.py

@@ -124,15 +124,7 @@ class Migration(migrations.Migration):
                 ("rdf_link", models.URLField(blank=True)),
                 ("loaded", models.BooleanField(default=False)),
                 ("loaded_time", models.DateTimeField(blank=True, null=True)),
-                (
-                    "root_object",
-                    apis_core.apis_metainfo.models.InheritanceForeignKey(
-                        blank=True,
-                        null=True,
-                        on_delete=django.db.models.deletion.CASCADE,
-                        to="apis_metainfo.rootobject",
-                    ),
-                ),
+                ("root_object", models.ForeignKey(blank=True, null=True, on_delete=django.db.models.deletion.CASCADE, to="apis_metainfo.rootobject")),
             ],
         ),
     ]

apis_core/apis_metainfo/models.py

@@ -4,7 +4,6 @@
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ImproperlyConfigured, ValidationError
 from django.db import models
-from django.db.models.fields.related_descriptors import ForwardManyToOneDescriptor
 from model_utils.managers import InheritanceManager
 
 from apis_core.generic.abc import GenericModel
@@ -37,17 +36,6 @@ def save(self, *args, **kwargs):
         super().save(*args, **kwargs)
 
 
-class InheritanceForwardManyToOneDescriptor(ForwardManyToOneDescriptor):
-    def get_queryset(self, **hints):
-        return self.field.remote_field.model.objects_inheritance.db_manager(
-            hints=hints
-        ).select_subclasses()
-
-
-class InheritanceForeignKey(models.ForeignKey):
-    forward_related_accessor_class = InheritanceForwardManyToOneDescriptor
-
-
 # Uri model
 # We use a custom UriManager, so we can override the queryset `get`
 # method. This way we can normalize the uri field.