feat(channels): channels package

[samuelmasse]

Moves all channels to their own package.

Each channel will have an api that will respect these standards :

const telegram = new TelegramChannel()
await telegram.setup(router)

telegram.on('message', async (e) => {
  await telegram.send(e.scope, e.endpoint, { text: 'yoyo' })
})

await telegram.start('gggg', { botToken: 'YOUR_CONFIG' })

Closes DEV-2125

[linear]

DEV-2125 Messaging make a channels package

Putting all channels in a single package will allow use to write v2 versions more easily, as well as decoupling the channel code from the server code, and reducing considerably the amount of code in the server package