Revise the app hosting/serving solution as per

MicroSoft's instruction:
https://techcommunity.microsoft.com/t5/ai-azure-ai-services-blog/deploy-a-gradio-web-app-on-azure-with-azure-app-service-a-step/ba-p/4121127

On branch main
Your branch is up to date with 'origin/main'.

Changes to be committed:
new file: host.py
modified: requirements.txt

host.py

@@ -0,0 +1,8 @@
+import gradio as gr
+from fastapi import FastAPI
+
+from app import iface
+
+app = FastAPI()
+
+app = gr.mount_gradio_app(app,iface,path="/")

requirements.txt

@@ -1,4 +1,5 @@
-openai
-gradio
-pandas
-# autoGPT
+openai==1.30.1
+gradio==4.31.5
+pandas==2.2.2
+fastapi==0.111.0
+gunicorn==22.0.0