Extend the startQRCodeDetection method to support customizing AVMetadataObject types.

[MemoryReload]

Bugfix:

1. fix a bug: the qrOutput doesn't get assigned in the startQRCodeDetection, after AVCaptureMetadataOutput creation , which makes stopQRCodeDetection useless.

Feature:

1. Extend the startQRCodeDetection method with a withTypes parameter to provide the ability to customize the code recognition types instead of the const type array [.qr, .ean8, .ean13, .pdf417]. And also provide a default value with the const types for withTypes parameter to make code compatible with old versions.

Optimize:

1. Dispatch the session configuration operation into the sessionQueue to make it more efficient (will not affect the main thread).

2. Make the qrOutput property accessible and type accurate, cause the user may need more configurations with the output (for example, the rectOfInterest).