### Why are the changes needed?
It's a common use case that the user may want to send the service logs in a structured format to Kafka and then collect them into centralized log services for further analysis, fortunately, the Kyuubi used logging frameworks Log4j2 has built-in [KafkaAppender](https://logging.apache.org/log4j/2.x/manual/appenders/message-queue.html#KafkaAppender) and [JSON Template Layout](https://logging.apache.org/log4j/2.x/manual/json-template-layout.html), thus the goal could be achieved by just a few configurations.
To simplify the user setup steps, this PR adds `log4j-layout-template-json-<version>.jar` into Kyuubi binary tarball.
PS: I also plan to support sending engine bootstrap process(e.g. `spark-submit`) logs into Kafka with specific labels in the follow-up PRs.
### How was this patch tested?
Manually test.
Configuration in `$KYUUBI_HOME/conf/log4j2.xml`
```xml
<Configuration status="INFO">
<Appenders>
<Kafka name="kafka" topic="ecs-json-logs" syncSend="false">
<JsonTemplateLayout>
<EventTemplateAdditionalField key="app" value="kyuubi"/>
<EventTemplateAdditionalField key="cluster" value="hadoop-testing"/>
<EventTemplateAdditionalField key="host" value="${hostName}"/>
</JsonTemplateLayout>
<Property name="bootstrap.servers" value="kafka-1:9092,kafka-2:9092,kafka-3:9092"/>
<Property name="compression.type" value="gzip"/>
</Kafka>
</Appenders>
<Loggers>
<Root level="INFO">
<AppenderRef ref="kafka"/>
</Root>
</Loggers>
</Configuration>
```
Check that Kafka receives the expected structured logging message in the Elastic Common Schema(ECS) layout.
### Was this patch authored or co-authored using generative AI tooling?
No
Closes#6861 from pan3793/structured-logging.
Closes#6861
9556da2a7 [Cheng Pan] Structured Logs
7dc6dda86 [Cheng Pan] Add log4j-layout-template-json
Authored-by: Cheng Pan <chengpan@apache.org>
Signed-off-by: Cheng Pan <chengpan@apache.org>
14e12e9aa4