Consolidate KafkaEventSubscriber and KafkaOutboxSubscriber into the former (GSI-1405)

[TheByronHimes]

Context:

DLQ retry topic subscription in select services

Problem description:

The services listed below run both event subscribers and outbox subscribers simultaneously.
This has not been a problem until now because the subscribed topics have been mutually exclusive.
The DLQ process introduced retry topics, of which there exists 1 per service.
Both retried outbox events and retried normal events both get funneled into the same retry topic for a service.
Both the outbox consumer and event consumer try to subscribe to the service's retry topic, but only one gets the events (barring a rebalance).

Affected Services:

• DINS
• NOS
• IRS
• DCS
• UCS

Notes:

1. In at least the NOS, the outbox subscriber is used for its intended purpose (cannot simply convert to event subscriber).
2. It is not practical to convert all events in a service to one type or the other as a way to use only one type of subscriber class, since that would require a cascade of changes in other services.

Preliminary Conclusion:

Given the problem stems from the fact that there are potentially two running consumers that listen to the same topic,
there are two obvious approaches to fix the problem:

1. Create another retry topic
2. Consolidate the consumers

[coveralls]

Pull Request Test Coverage Report for Build 13410390804

Details

• 25 of 28 (89.29%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.04%) to 92.148%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/hexkit/providers/akafka/provider/eventsub.py	24	27	88.89%

Totals
Change from base Build 13073068960:	-0.04%
Covered Lines:	1995
Relevant Lines:	2165

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💛 - Coveralls