Add required kwd to slot tag and add test

Move required slot check to SlotNode.render(); clean up needed

Remove unused code; drop caching

Update docs

Incorporate PR feedback

tests/django_test_setup.py

@@ -10,12 +10,11 @@ if not settings.configured:
                 "DIRS": ["tests/templates/"],
             }
         ],
-        COMPONENTS={"template_cache_size": 128, "strict_slots": False},
+        COMPONENTS={"template_cache_size": 128},
         MIDDLEWARE=[
             "django_components.middleware.ComponentDependencyMiddleware"
         ],
         DATABASES={},
-        # DEBUG=True
     )
 
     django.setup()