Add A2dp decode software and offload session type

1. Add the interface
2. Add the default implementation
3. Add VTS

Bug: 206601670
Test: atest VtsHalBluetoothAudioTargetTest
Change-Id: I54d8037eeb09312c9f1fb75d2167cc50ac7cae8c
diff --git a/bluetooth/audio/aidl/default/A2dpOffloadAudioProvider.h b/bluetooth/audio/aidl/default/A2dpOffloadAudioProvider.h
index 4621e85..e6f188b 100644
--- a/bluetooth/audio/aidl/default/A2dpOffloadAudioProvider.h
+++ b/bluetooth/audio/aidl/default/A2dpOffloadAudioProvider.h
@@ -40,6 +40,16 @@
   ndk::ScopedAStatus onSessionReady(DataMQDesc* _aidl_return) override;
 };
 
+class A2dpOffloadEncodingAudioProvider : public A2dpOffloadAudioProvider {
+ public:
+  A2dpOffloadEncodingAudioProvider();
+};
+
+class A2dpOffloadDecodingAudioProvider : public A2dpOffloadAudioProvider {
+ public:
+  A2dpOffloadDecodingAudioProvider();
+};
+
 }  // namespace audio
 }  // namespace bluetooth
 }  // namespace hardware