Python 3.10 : Threading related deprecations

[tirkarthi]

Ref : python/cpython#25174

Camelcase aliases have been deprecated and raise deprecation warning.

notifyAll -> notify_all
currentThread -> current_thread

opendxl-client-python/dxlclient/_request_manager.py:                    self.sync_wait_message_condition.notifyAll()
opendxl-client-python/dxlclient/client.py:                self._connect_wait_condition.notifyAll()
opendxl-client-python/dxlclient/client.py:        if threading.currentThread().name.startswith(self._message_pool_prefix):