Webhook support

[bemyak]

It would be very nice if telebot had support of webhooks.
If you're writing telegram bot on Rust than you probably expect extreamly high performance and "pull" method is something opposite to it :)

[tecywiz121]

The pull method is supposed to be long polling, so the performance shouldn't be that terrible.

That said, if you want to scale beyond a single process polling, I suspect the webhooks method is probably the way to go.

[bytesnake]

The library did not used long polling up to this point, but I added support in 6a632d7 and telebot will now wait 30s before it sends a new request.
Nevertheless it would be nice to support webhooks. But first we need to switch the underlying infrastructure from cURL to hyper to have server support and then extend the Bot struct to host a server. #21

[bytesnake]

This is blocked until a library for multiform server AND client support is published. The best candidate ist https://github.com/abonander/multipart-async, but it has no client support yet.