Add LLM configuration and update URL routing

- Introduced LLM configuration in rag_config.yaml and corresponding LLMConfig class in config.py.
- Updated load_rag_config function to parse LLM settings from the configuration file.
- Added new API route for RAG in urls.py to facilitate access to the chat model.
- Modified QdrantVectorStore to use query_points method for improved functionality.

rag/urls.py

@@ -0,0 +1,7 @@
+from django.urls import path
+
+from .views import ChatView
+
+urlpatterns = [
+    path("chat/", ChatView.as_view()),
+]