Until now, the instructions on generating wasm files and using them
for Scylla UDFs were stored in docs/dev, so they were not visible
on the docs website. Now that the Rust helper library for UDFs
is ready, and we're inviting users to try it out, we should also
make the rest of the Wasm UDF documentation readily available
for the users.
Closes#13139
52eb70aef0