ZXING should not be included due to system.drawing dependencies

[Theoistic]

until now we've used this library as a direct git submodule .. to keep the integration clean,
but adding dependencies on system.drawing breaks our implementation. since the library is used in our PWA (WebAssembly does not support this due to glibc and other dependencies which system.drawing requires.)
our QR's are generated from PNG or SVG sources natively, this should also be an opt-in service. or split it in two separate assembly at the very least..