Add Android APK for Silero VAD (#335)

sherpa-onnx/csrc/silero-vad-model.h

@@ -6,6 +6,11 @@
 
 #include <memory>
 
+#if __ANDROID_API__ >= 9
+#include "android/asset_manager.h"
+#include "android/asset_manager_jni.h"
+#endif
+
 #include "sherpa-onnx/csrc/vad-model.h"
 
 namespace sherpa_onnx {
@@ -13,6 +18,11 @@ namespace sherpa_onnx {
 class SileroVadModel : public VadModel {
  public:
   explicit SileroVadModel(const VadModelConfig &config);
+
+#if __ANDROID_API__ >= 9
+  SileroVadModel(AAssetManager *mgr, const VadModelConfig &config);
+#endif
+
   ~SileroVadModel() override;
 
   // reset the internal model states