Support crt logs in 'logging' module

[azkrishpy]

Issue #, if available:

Description of changes:
CRT log messages can now be routed through Python's standard logging module via the awscrt.logging module.

Usage:

import logging
from awscrt.logging import init_logging, CRT_LOG_FORMAT

handler = logging.StreamHandler()
handler.setFormatter(logging.Formatter(CRT_LOG_FORMAT))
logging.getLogger('awscrt').addHandler(handler)
init_logging(logging.DEBUG)

Note: Existing awscrt.io.init_logging() is retained for backward compatibility, however CRT cannot publish to multiple subscribers, so only one of the loggers can be initialized.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[TingDaoK]

wow, this is hacky, I spent 5 mins to understand this...