TZIP-16: we need to be more precise about encoding of the URI (in the metadata big-map)
It seems there are examples in the wild of people using PACK
to put the URI in the big-map.
⇒ We should make sure that is not considered standard, the bytes
should be the URI (encoded as in the RFC), no need to PACK
for off-chain use.
Cc @m-kus