Hi, all, I want to submit a minor kip to add a metric, which supports to get the running kafka server verison, the wiki url is here
Motivation At present, it is impossible to perceive the Kafka version that the broker is running from the perspective of metrics. If multiple Kafka versions are deployed in a cluster due to various reasons, it is difficult for us to intuitively understand the version distribution. So, I want to add a kafka version metric indicating the version of the current running kafka server, it can help us to perceive the mixed distribution of multiple versions, and to perceive the progress of version upgrade in the cluster in real time. Proposed Changes When instantiating kafkaServer/BrokerServer, register `KafkaVersion` gauge metric, whose value is obtained by `VersionInfo.getVersion`. And remove all related metrics when kafkaServer/BrokerServer shutdown. best, hudeqi
