guide(jwt): Create a guide to show JWT signing with Arweave keypairs and the verification of these JWT

[jim-toth]

It might be worth using the jsonwebtoken npm library to show verification is standard but maybe also include a way to verify it via Arweave.crypto

Here's an example of how to accomplish JWT creation and signing using an arbundles compatible signer in use in the art by city dapp: https://gitlab.com/art-by-city/art-by-city/-/blob/master/plugins/artbycity/index.ts#L79

and signer: https://gitlab.com/art-by-city/art-by-city/-/blob/master/app/infra/arweave/signer/arweaveWalletSigner.ts