Update and rename 47.1. Extend configuration to 47.1. Extend configuration.md

V. Spring Boot Actuator: Production-ready features/47.1. Extend configuration.md

@@ -0,0 +1,8 @@
+### 47.1. 扩展属性
+
+你需要激活`META-INF/spring.factories`文件里的listener(s)：
+```java
+org.springframework.context.ApplicationListener=\
+org.springframework.boot.actuate.system.ApplicationPidFileWriter,
+org.springframework.boot.actuate.system.EmbeddedServerPortFileWriter
+```