FEATURE: SSKR Shards to separate PDFs/NFC

This is really three intertwined features:

1 - Ability to save the SSKR scenario rnd() data used to generate a SSKR "session" to internal metadata of seed (?? local only or cloud also??), such that the next time you generate SSKR you have the option "Do you want to reprint the last session (keeping the last scenario and share the same values) or generate a new session (new scenario and new values)? (@shannona can you suggest a different text and define language for session and values?)

2 - Ability to share sequentially each shard separately, and mark each as completed.
a - QR
b - UR text or single page PDF to potentially different files system (dropbox, sd card, etc.)
c - UR text to NFC cards (see feature #124 )
d - potentially future devices

3 - Ability to delete seed private values, keeping lifehash, fingerprints, and master public key, and IDs for SSKRs generated in past and ability to crypto-request seed, sskr or master private key back temporarily when a signature is requested for that key, deleting it after.