QR account export format

[BullishNode]

Apparently some hardware wallets like Jade and SeedSigner use a wallet xpub format that is some kind of standard which uses multiple QR code frames. Its not just a straight xpub, it has other data like derivation paths.
To investigate

[i5hi]

When i tried a few days ago scanning from Jade, I noticed a 1/5, 2/5, 3/5, n/5 prepended to the encoded data.

A normal qr scanner just captures one and closes.

I think we have to keep reading until we get to all 5/5 and then remove the n/5 and join the encoded data.

[i5hi]

Related to https://github.com/SatoshiPortal/bb-mobile/issues/127

[i5hi]

Resources:

BlockchainCommons/Gordian-Developer-Community#4

[i5hi]

https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-005-ur.md

[i5hi]

From this discussion on stackoverflow https://stackoverflow.com/questions/68829095/flutter-qrcode-successive-scans

https://pub.dev/packages/qr_code_scanner

Seems to be a library that could handle it. Allows us to set our own logic for how to scan QR. We could have a custom, multi-frame mode ?

@mocodesmo