feat: create chat engine folder for python

packages/create-llama/questions.ts

...a/templates/components/vectordbs/python/none/constants.py

...ama/templates/components/vectordbs/python/none/context.py

...ma/templates/components/vectordbs/python/none/generate.py

...llama/templates/components/vectordbs/python/none/index.py

packages/create-llama/templates/index.ts

...ma/templates/types/simple/fastapi/app/api/routers/chat.py

...-llama/templates/types/simple/fastapi/app/engine/index.py

...te-llama/templates/types/streaming/fastapi/app/context.py

.../templates/types/streaming/fastapi/app/engine/__init__.py

...ama/templates/types/streaming/fastapi/app/engine/index.py