INTEXT-191: Add Apache Kafka Sample

JIRA: https://jira.spring.io/browse/INTEXT-191

Polishing and build.gradle fix for pom generation

basic/kafka/src/main/resources/application.yml

@@ -0,0 +1,7 @@
+kafka:
+  broker:
+    address: localhost:9092
+  zookeeper:
+    connect: localhost:2181
+  topic: si.topic
+  messageKey: si.key

basic/kafka/src/main/resources/logback.xml

@@ -0,0 +1,14 @@
+<configuration>
+
+  <appender name="STDOUT" class="ch.qos.logback.core.ConsoleAppender">
+    <!-- encoders are assigned the type
+         ch.qos.logback.classic.encoder.PatternLayoutEncoder by default -->
+    <encoder>
+      <pattern>%d{HH:mm:ss.SSS} [%thread] %-5level %logger{36} - %msg%n</pattern>
+    </encoder>
+  </appender>
+
+  <root level="warn">
+    <appender-ref ref="STDOUT" />
+  </root>
+</configuration>