CDC-to-Kafka 3.2.0

1. Reverts to using Python v3.8 in the Dockerfile, due to process-hang issues associated with changes that were released in Python v3.9
2. Implements limited in-process retrying of timed out SQL queries, instead of always relying on process crash and supervisor restart mechanics
3. Makes the row batch size for DB queries configurable (but still defaults to the original 2,000)
4. Logging improvements and cleanups
5. Fixes a bug that could cause progress hearbeat messages to be emitted with an LSN lower than the last previously published progress message for a table
6. Moves HTTP-based metrics reporting to a separate thread to reduce latency impact on the main process
7. Introduces progress_reset_tool.py, which can be used to delete progress entries for specific topic(s), e.g. to trigger re-taking a snapshot without needing to create a new capture instance in the DB
8. Improves logic in both the progress-topic and regular-topic validator tools
9. Allows use of pseudo-failover in cases where connections to the primary server time out entirely