Add VAD+ASR demo for HarmonyOS (#1573)

harmony-os/SherpaOnnxVadAsr/entry/hvigorfile.ts

@@ -0,0 +1,6 @@
+import { hapTasks } from '@ohos/hvigor-ohos-plugin';
+
+export default {
+    system: hapTasks,  /* Built-in plugin of Hvigor. It cannot be modified. */
+    plugins:[]         /* Custom plugin to extend the functionality of Hvigor. */
+}