MINOR: Inline "Running a Kafka broker in KRaft mode" (#12750)

Also moved KRaft mode above zk mode.

Reviewers: Mickael Maison <mimaison@users.noreply.github.com>

README.md

@@ -83,15 +83,17 @@ fail due to code changes. You can just run:
  
     ./gradlew processMessages processTestMessages
 
+### Running a Kafka broker in KRaft mode
+
+    KAFKA_CLUSTER_ID="$(./bin/kafka-storage.sh random-uuid)"
+    ./bin/kafka-storage.sh format -t $KAFKA_CLUSTER_ID -c config/kraft/server.properties
+    ./bin/kafka-server-start.sh config/kraft/server.properties
+
 ### Running a Kafka broker in ZooKeeper mode
 
     ./bin/zookeeper-server-start.sh config/zookeeper.properties
     ./bin/kafka-server-start.sh config/server.properties
 
-### Running a Kafka broker in KRaft (Kafka Raft metadata) mode
-
-See [config/kraft/README.md](https://github.com/apache/kafka/blob/trunk/config/kraft/README.md).
-
 ### Cleaning the build ###
     ./gradlew clean