feat: add standardized debug logging

[jackwotherspoon]

Standardize optional debug logging across AlloyDB Connector packages.

To print debug logs for the Python Connector package add the following to your application:

import logging

logging.basicConfig(format="%(asctime)s [%(levelname)s]: %(message)s")
logger = logging.getLogger(name="google.cloud.alloydb.connector")
logger.setLevel(logging.DEBUG)

Example of the debug logs produced:

2024-07-24 17:52:05,231 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Refresh strategy is set to background refresh
2024-07-24 17:52:05,231 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Connection info added to cache
2024-07-24 17:52:05,231 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Connection info refresh operation started
2024-07-24 17:52:05,881 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Connection info refresh operation complete
2024-07-24 17:52:05,882 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Current certificate expiration = 2024-07-24T18:52:04+00:00
2024-07-24 17:52:05,882 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Connection info refresh operation scheduled for 2024-07-24T18:22:06+00:00 (now + 0:30:01)
2024-07-24 17:52:05,882 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Connecting to 127.0.0.1:5433
2024-07-24 17:52:06,458 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Canceling connection info refresh operation tasks
2024-07-24 17:52:06,458 [DEBUG]: ['projects/my-proj/locations/us-central1/clusters/my-cluster/instances/my-instance']: Scheduled refresh operation cancelled
2024-07-24 17:52:06,458 [DEBUG]: Waiting for connector's http client to close
2024-07-24 17:52:06,459 [DEBUG]: Closed connector's http client

Currently debug logging the following:

• When a refresh operation starts
• When a refresh operation finishes
• When a refresh operation errors
• When a refresh operation is canceled
• The ephemeral certificate’s expiration time
• The next scheduled refresh
• Adding connection info to the cache
• The IP address connection is being made to

Fixes #272

[enocom]

Thank you! ❤️ ❤️