[SRVLS] Docs: Kafka Sink creation

Dependencies

https://github.com/openshift/openshift-docs/pull/50130 is work being done in Serverless docs to move around the structure of Kafka docs. A PR for this issue should not be merged until after PR 50130 is merged. Work with pchandra@redhat.com to identify a best location for the update in the docs. As the Kafka docs are a bit in flux, we may need to be flexible as we work with the Serverless team to get this placed correctly. 

Background

This issue involves an update to Serverless docs, related to Kafka. Serverless writers are working on Kafka GA coming out soon. However, this engineering epic is tied to OCP 4.12 so we don't have to adhere to the Kafka GA deadline. 

Review process

Recommended review for this issue:

1. ODC SME (epic assignee, or Jai if we need a point of contact) and Serverless Eventing SME (Slack channel: #serverless-dev, tag group @eventing-team)
2. ODC QE and Serverless QE (Slack channel: #serverless-qe, tag group @ocf-qe-team) 
3. Normal peer review process

Scope

Details and sizing will be added.