Add Python logging.Handler for LogKeeper V3

Add a logging.Handler subclass similar to existing BuildloggerTestHandler class that talks to Jasper through the LoggingCache interface. The class will implement the StreamHandler interface.

Ideally there would not be any caching done on the resmoke side since cache pressure is one of the pain points of LogKeeper v2.

The handler will be exercised in an automated unit test that logs to stdout. Integration with the rest of resmoke's logging structure and Cedar will be done in a separate ticket.