Add logging.level to application.properties

E.g.

logging.level.org.springframework: DEBUG
logging.level.org.hibernate: WARN

Fixed gh-788

spring-boot-samples/spring-boot-sample-actuator/src/main/resources/application.properties

@@ -1,4 +1,5 @@
 logging.file: /tmp/logs/app.log
+logging.level.org.springframework.security: INFO
 management.address: 127.0.0.1
 endpoints.shutdown.enabled: true
 server.tomcat.basedir: target/tomcat

spring-boot-samples/spring-boot-sample-actuator/src/main/resources/logback.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<configuration>
-	<include resource="org/springframework/boot/logging/logback/base.xml"/>	
-	<!-- logger name="org.springframework.boot" level="DEBUG"/-->
-	<!-- logger name="org.springframework.security" level="DEBUG"/-->
-</configuration>