added streaming fastapi template

packages/create-llama/templates/.gitignore

...eate-llama/templates/streaming/fastapi/README-template.md

.../create-llama/templates/streaming/fastapi/app/__init__.py

...ate-llama/templates/streaming/fastapi/app/api/__init__.py

...a/templates/streaming/fastapi/app/api/routers/__init__.py

...llama/templates/streaming/fastapi/app/api/routers/chat.py

...reate-llama/templates/streaming/fastapi/data/brk-2022.pdf

packages/create-llama/templates/streaming/fastapi/gitignore

packages/create-llama/templates/streaming/fastapi/main.py

...s/create-llama/templates/streaming/fastapi/pyproject.toml

...reate-llama/templates/streaming/fastapi/tests/__init__.py