Allow users to freely create Webhook handlers

[hota1024]

🎏 Goals

• ⬇️ Bundle size reduction
• 🚀 Support for serverless environments
• ➖ Remove express package

💡 Ideas

The ActivityActivityControllable#emit(body: ActivityEvent): Promise<void> and ActivityControllable#crc(): CrcResponse methods

/* Twict */
const activity = new Activity('{LABEL}', { /* options */ })
activity.onFavoriteEvent(() => /* ... */)

/* express */
const app = express()
app.get('/', (req, res) => {
  const crcToken = req.query.crc_token

  if (typeof crcToken === 'string') {
    res.send(activity.crc()) // Activity#crc(): CrcResponse
  } else {
    res.status(400).send('crc_token missing from request.')
  }
})
app.post('/', ({ body }) => activity.emit(body)) // Activity#emit(body: ActivityEvent): Promise<void>

[winstxnhdw]

I am not very experienced in TypeScript/JavaScript patterns but grammY, a Telegram bot framework, uses adapters.

See this https://github.com/grammyjs/grammY/blob/main/src/convenience/frameworks.node.ts