parametrize timeout in https://github.com/toncenter/pytonlib/blob/main/pytonlib/tonlibjson.py#L199 to be able to raise it

[imzaur]

I am having issue

line 207, in read_results
    result = await asyncio.wait_for(self.loop.run_in_executor(None, receive_func), timeout=timeout + delta)
  File "/usr/lib/python3.9/asyncio/tasks.py", line 466, in wait_for
    await waiter
asyncio.exceptions.CancelledError

would be nice to have opportunity to increase task waiting timeout