Add message when ASGI and WSGI is enabled

[Hazhzeng]

Related Issues

Fix: #71
Fix: Azure/azure-functions-python-worker#839

Description

1. Now when the WSGI and ASGI middleware start, we will emit Instantiating Azure Functions ASGI middleware. or Instantiating Azure Functions WSGI middleware. log message for the very first time when the middleware instantiated either in main = WsgiMiddleware(app) syntax or def func(req, context): return WsgiMiddleware(app).handle(req, context) syntax.
2. Fix an issue where the middlewares fail to accept the context parameter.

Todo

1. In the worker, we need to direct azure.functions log into system log category.

cc: @tonybaloney @stefanushinardi @vrdmr

[github-actions]

✅ Result of Pytest Coverage

[vrdmr]

LGTM 🚢

nit - comments wherever needed.