KERNEL-14695 fix: 链路追踪Span是否可以忽略

fine-skywalking-toolkit-trace/src/main/java/org/apache/skywalking/apm/toolkit/trace/Trace.java

@@ -35,4 +35,9 @@ public @interface Trace {
      * @return operation name, the default value is blank string.
      */
     String operationName() default "";
+
+    /**
+     * 是否可以被忽略
+     */
+    boolean ignorable() default true;
 }