[Idea] Mention an alternative way of backing up the binary file

[jose1711]

Approx. 11.5 KB (highest ECC level) to 13.7 KB (lowest ECC level) of 8-bit data can be encoded just by using qrencode (using structured symbols) and imagemagick. Maybe this could be mentioned in the README as an alternative for people looking for ways to store some binary data (instead of going through base64).

curl -s https://www.gnu.org/software/gettext/manual/gettext.txt | dd bs=1 count=14100 2>/dev/null >/tmp/gettext.txt
qrencode -S -8 -v30 -o /tmp/qr.png -r /tmp/gettext.txt
montage /tmp/qr-*.png -geometry 640x640 /tmp/qr_complete.pdf
# restore the file
zbarimg --raw /tmp/qr_complete.pdf >/tmp/gettext.txt.restored
# verify (perhaps we can ignore the added newline)
diff /tmp/gettext.txt /tmp/gettext.txt.restored 

395c395
< males or females.  Besides, 
\ No newline at end of file
---
> males or females.  Besides,