Replace the sequential upload to concurrent upload. and only use one connection at a time

And most of them come from https://github.com/Nekmo/telegram-upload/blob/master/telegram_upload/client/telegram_upload_client.py

I simplified it, only kept the upload function, and made some optimizations.

Old (sequential):

New (concurrent):

1. Support GUI file batch selection
2. Support re-upload after failure
3. Support Concurrent-Upload (Fast speed)

uv run main.py

uv run concurrent_upload.py