Add Kafka log retention

Related to https://gitlab.com/gitlab-org/analytics-section/product-analytics/analytics-stack/-/issues/34

Similar to https://gitlab.com/gitlab-org/analytics-section/product-analytics/analytics-stack/-/merge_requests/45 for the analytics-stack this sets the Kafka Log Retention explicitly.

We are still using the default retention of 7 days here. Especially on local I'd not expect high enough event volumes for storage to become a concern but it might still be necessary to flush Kafka from time to time. This also brings the devkit on par with the analytics-stack when it comes to the settings we set explicitly