Two scripts to create qr codes from a private key and to restore them.

Use "create_codes" to create a pdf "qr.private.pdf" with arranged qrcodes (it
takes the key id as an input).

When restoring, scan the qr codes in the order of their numbers, put the parts
into numbered txt files and run the "restore_key" script with the first arg being
the path to the public key and the second one the path to the directory with the
txt files.