KAFKA-10473: Add docs on partition size-on-disk, and other log-related metrics (#9276)
KAFKA-10473: Add docs on partition size-on-disk, and other log-related metrics (#9276)

kafka.log,type=Log,name=Size
kafka.log,type=Log,name=NumLogSegments
kafka.log,type=Log,name=LogStartOffset
kafka.log,type=Log,name=LogEndOffset

Reviewers: Guozhang Wang <fae442ba222671b2ebdf7511c9ca77079c43031b@gmail.com>
TiVo/kafka,TiVo/kafka,guozhangwang/kafka,Chasego/kafka,Chasego/kafka,apache/kafka,guozhangwang/kafka,apache/kafka,Chasego/kafka,lindong28/kafka,lindong28/kafka,lindong28/kafka,apache/kafka,TiVo/kafka,apache/kafka,guozhangwang/kafka,lindong28/kafka,guozhangwang/kafka,Chasego/kafka,TiVo/kafka