👔(backend) add Organization model

We introduce the Organization model has a "hat" for all
users and team.

Each User must have a "default" organization.
Each Team must have an organization.

When a User creates a new Team, the team is linked to their
default Organization.

For now the Organization should not be visible to end users
this is a purely technical aspect as it.

The models are also adding a permission to allow User to edit
an Organization, but for now there are no endpoints for that.

Next steps:
- Add an Organization to each User and Team on all environments
  to mark Organization as mandatory in database.
- Add scope to Organization to list the Service Provider list
  allowed for a User in an Organization.
- Add endpoints + frontend to manage Organization's scopes

src/backend/core/api/serializers.py

@@ -194,6 +194,14 @@ class TeamSerializer(serializers.ModelSerializer):
             "updated_at",
         ]
 
+    def create(self, validated_data):
+        """Create a new team with organization enforcement."""
+        # Note: this is not the purpose of this API to check the user has an organization
+        return super().create(
+            validated_data=validated_data
+            | {"organization_id": self.context["request"].user.organization_id}
+        )
+
     def get_abilities(self, team) -> dict:
         """Return abilities of the logged-in user on the instance."""
         request = self.context.get("request")