Move configuration from config.py to config.json and add support for GitHub organization webhooks

remove _format_watch() from utils.github_webhook as the value of
watchers_count is always identical with stargazers_count
https://docs.github.com/en/developers/webhooks-and-events/webhook-events-and-payloads#watch
https://developer.github.com/changes/2012-09-05-watcher-api/

main.py

@@ -18,6 +18,7 @@
 
 """
 import asyncio
+from typing import Union
 
 from aiohttp import web, ClientSession
 from aiohttp.web_request import Request
@@ -39,10 +40,10 @@ async def main(_):
 
 @routes.post("/")
 async def github_webhook_post_handler(request: Request) -> Response:
-    valid_github_webhook = await validate_github_webhook(request)
-    if not valid_github_webhook:
+    tg_chat_id: Union[str, int, bool] = await validate_github_webhook(request)
+    if not tg_chat_id:
         return web.Response(status=403, text="403: Forbidden")
-    tg_status = await send_to_telegram(session, request)
+    tg_status = await send_to_telegram(session, tg_chat_id, request)
     return web.Response(text=f"Send to Telegram: {tg_status}")