INTSAMPLES-150: Switch to Log4j2

JIRA: https://jira.spring.io/browse/INTSAMPLES-150

basic/web-sockets/src/main/resources/logback.xml

@@ -0,0 +1,19 @@
+<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>
+
+	<logger name="org.springframework" level="WARN" />
+	<logger name="org.springframework.integration" level="ERROR" />
+
+</configuration>