srowen [SPARK-25705][BUILD][STREAMING][TEST-MAVEN] Remove Kafka 0.8 integration
## What changes were proposed in this pull request?

Remove Kafka 0.8 integration

## How was this patch tested?

Existing tests, build scripts

Closes #22703 from srowen/SPARK-25705.

Authored-by: Sean Owen <sean.owen@databricks.com>
Signed-off-by: Sean Owen <sean.owen@databricks.com>
Latest commit 703e6da Oct 16, 2018