Add support for custom QR code image

[Klakurka]

Add support for custom QR code image. This is currently always set to the orange BCH logo.

[Klakurka]

The logo colour can (now) be changed now but that's it.

[Klakurka]

We're not 100% sure we need to go ahead with this as we have custom colours happening so we'll backburner this for now.

[Klakurka]

This could tie into #64.