Evaluate other types of barcodes and make them configurable.

[jcgruenhage]

There's a lot more in https://en.wikipedia.org/wiki/Barcode#Types_of_barcodes and some other matrix codes are more efficient than QR. We should not limit this tool to only QR codes.

[margau]

I'm planning to refactor main.py to use better OOP-Style Code, i'd like to add new features in this area only after that has happened.