Document the utility to decrypt mobile wallet export

[abizjak]

Task description

The "utils" utility https://github.com/Concordium/concordium-base/blob/main/rust-bins/src/bin/utils.rs is the only way to decrypt the wallet export file that is sometimes needed when integrating with the chain.

We should link to binaries and document how to use.

Sub-tasks

• [ ] Add links to download the utility
• [ ] Document how to use

Add label for component and priority.

[dg-concordium]

@abizjak Can you provide info about how to run and make available for download?

[abizjak]

I'll provide links tomorrow, regarding how to run, it is just the following two commands

utils encrypt --in input.blah --out output.json

where --in ... is the file to encrypt, and --out is the file where encrypted data will be written. This will result in the following interaction

Enter password to encrypt with: ....
Re-enter password: ....
Writing output to output.json

Dually, to decrypt

utils decrypt --in output.json --out decrypted.blah

Enter password to decrypt with: Writing output to decrypted.blah

With `--in ...` being the encryptd file, and `--out` the decryption.

Let me know if this is enough information.

For an introduction about why you need this tool, I would say something along the lines of "Some concordium tools, such as the mobile wallet, sometimes produce encrypted output. These files can be decrypted and inspected using the `utils` tool ..."