Improve Documentation for Installing Kafka Connect

Feature Request / Improvement

The current installation instructions for Kafka connect seem to leave a bit of ambiguity that makes it difficult for users to get started. We should specify exactly what is required to start and in the future we should have a more complete solution which doesn't require building the project.

https://iceberg.apache.org/docs/nightly/kafka-connect/#installation

Currently doesn't mention what the zip is called or if the zip needs to be extracted which seems to be the case according to #12507

See #12507 for more details

Query engine

Kafka Connect

Willingness to contribute

• I can contribute this improvement/feature independently
• I would be willing to contribute this improvement/feature with guidance from the Iceberg community
• I cannot contribute this improvement/feature at this time