Clean permission request mechanism

FrameExtractor.swift

init() {
    checkPermission()
    sessionQueue.async { [unowned self] in
        self.configureSession()
        self.captureSession.startRunning()
    }
}
    
// MARK: AVSession configuration
private func checkPermission() {
    switch AVCaptureDevice.authorizationStatus(forMediaType: AVMediaTypeVideo) {
    case .authorized:
        permissionGranted = true
    case .notDetermined:
        requestPermission()
    default:
        permissionGranted = false
    }
}
    
private func requestPermission() {
    sessionQueue.suspend()
    AVCaptureDevice.requestAccess(forMediaType: AVMediaTypeVideo) { [unowned self] granted in
        self.permissionGranted = granted
        self.sessionQueue.resume()
    }
}