feat: Expose option for user to edit max_queue_size in websockets, have async callbacks called in a task and update docs

[pcriadoperez]

• Move MAX_QUEUE_SIZE from constant to variable set by user on starting ThreadedWebsocket or BinanceWebsocket
• Have async callbacks run in a task to better performance of slow async callbacks. (Before one had to finish before calling the next one)
• Fix passing keys and proxy to threaded socket manager
• Adds pytest-timeout and timeout of 60seconds for tests
• Add tests
• Update docs
• Increase verbosity in test running
• Comments coveralls: (Temporarily due to due to coveralls maintenance of April 6 2025: https://status.coveralls.io/)