Preserve message order when bridging from Telegram to Matrix

[tulir]

Currently the bridge processes incoming messages in parallel and doesn't care about message order at all. This means that groups of forwarded messages, image albums and even normal messages may be bridged to Matrix out of order.

The solution is enabling sequential_updates=True in TelegramClient, but before that, media uploads need to become asynchronous (so that a big file being bridged doesn't block all other messages). Asynchronous media uploads while preserving message order requires matrix-org/matrix-spec-proposals#2246.

[JuniorJPDJ]

What if you just edit message after sending a file?
It would probably break other things like facebook bridging, but it seems like pretty good workaround.