change codeReader to a prop, so it can be reused for multiple instances

[HuyHHV]

If multiple instances of barcode reader are used, the loading time will be extremely long and the web page become laggy. This can be solved by declaring BrowserMultiFormatReader() in a parent component and sharing it with other barcode reader instances using prop. The codeReader also has a default value: new BrowserMultiFormatReader(), if only one barcode reader instance is used

[teckel12]

@HuyHHV I haven't experienced this as I use the barcode scanner as a component already. But does this "trick" really help?