Add API.py

Added a link to streaming demo on Huggingface

support stream chat

Fix model name

streamlit based web_demo

Add some parameter support in web demo

Add a steamlit based demo web_demo2.py for better UI.
need to install streamlit and streamlit-chat component fisrt:
pip install streamlit
pip install streamlit-chat

then run with the following:
streamlit run web_demo2.py --server.port 6006