ArcfaceDemo_support_AndroidCamera2

Add support for Android Camera2 based on ArcSoft 3.0 Demo

Change Logs:
2020-09-18

1. Added com.arcsoft.arcfacedemo.util.camera.Camera2Helper based on the original ArcFaceDemo.
2. Modified com.arcsoft.arcfacedemo.activity.FaceAttrPreviewActivity (for face attribute detection in video), changing from using cameraHelper to camera2Helper.
3. Other functions in the demo remain unmodified for now, but you can refer to FaceAttrPreviewActivity for switching between camera1 and camera2 usage.