[alerter,manager] 告警信息入库，监控状态变更联动

common/src/main/java/com/usthe/common/util/CommonConstants.java

@@ -87,4 +87,9 @@ public interface CommonConstants {
      * 可用性对象
      */
     String AVAILABLE = "available";
+
+    /**
+     * 可达性对象
+     */
+    String REACHABLE = "reachable";
 }