Dynamically define dlq and retry topics (GSI-1175)

[TheByronHimes]

akafka/config.py

• Removed the config values for the two topics (kafka_dlq_topic and kafka_retry_topic). The former is generated by appending KafkaConfig.service_name and -dlq to the end of the vanilla topic name, with a . between. Example: regular topic is 'some-topic', the service name is 'my-service', and the dlq topic that 'my-service' uses for erroring events from 'some-topic' is 'some-topic.my-service-dlq'.
• Removed the validator because the fields it validated are gone

akafka/eventsub.py

• Add a small function for getting the service name from a DLQ topic name
• Dynamically form and subscribe to retry topic based on configured service_name.
• Remove original_topic header for the first half of the DLQ flow (it's not needed or included when publishing a failed event to the DLQ because the topic name is preserved in the DLQ topic's name)
• In KafkaEventSubscriber._extract_info(), it will get the original topic value from the DLQ topic name instead of the old header
• In KafkaDLQSubscriber, The retry topic is no longer an init variable because that information is, again, pulled from the service name (which is embedded in the DLQ topic name).

Tests

• Since the config is simplified, we don't need a bunch of tests to make sure the config validation works.
• Renamed the subscriber instances to either event_subscriber or dlq_subscriber for clarity
• Moved "test-topic" and "test-type" into constants
• Added a few comments for clarity
• Updated the log assertions that included topic names (previously the test names were dlq or retry, but these are now test-topic.test-dlq or test-retry)
• Replaced one use of a translator with an AsyncMock because the translator wasn't actually used (around L590)
• Use constant DLQ and retry topics since the tests all use the same topic and event types

[coveralls]

Pull Request Test Coverage Report for Build 11972958588

Details

• 15 of 18 (83.33%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.1%) to 92.311%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/hexkit/providers/akafka/provider/eventsub.py	14	17	82.35%

Totals
Change from base Build 11913210287:	-0.1%
Covered Lines:	2053
Relevant Lines:	2224

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💛 - Coveralls