♻️(backend) rename DomainInvitation

All models relacted to mail domain are prefixed
with "MailDomain". Do the same for mail domain invitations.

src/backend/mailbox_manager/api/client/serializers.py

@@ -269,11 +269,11 @@ class MailDomainAccessReadOnlySerializer(MailDomainAccessSerializer):
         ]
 
 
-class DomainInvitationSerializer(serializers.ModelSerializer):
+class MailDomainInvitationSerializer(serializers.ModelSerializer):
     """Serialize invitations."""
 
     class Meta:
-        model = models.DomainInvitation
+        model = models.MailDomainInvitation
         fields = ["id", "created_at", "email", "domain", "role", "issuer", "is_expired"]
         read_only_fields = ["id", "created_at", "domain", "issuer", "is_expired"]
 

src/backend/mailbox_manager/api/client/viewsets.py

@@ -294,7 +294,7 @@ class MailBoxViewSet(
         return Response(serializers.MailboxSerializer(mailbox).data)
 
 
-class DomainInvitationViewset(
+class MailDomainInvitationViewset(
     mixins.CreateModelMixin,
     mixins.ListModelMixin,
     mixins.RetrieveModelMixin,
@@ -320,11 +320,11 @@ class DomainInvitationViewset(
     lookup_field = "id"
     permission_classes = [permissions.AccessPermission]
     queryset = (
-        models.DomainInvitation.objects.all()
+        models.MailDomainInvitation.objects.all()
         .select_related("domain")
         .order_by("-created_at")
     )
-    serializer_class = serializers.DomainInvitationSerializer
+    serializer_class = serializers.MailDomainInvitationSerializer
 
     def get_serializer_context(self):
         """Extra context provided to the serializer class."""