Add web5 CLI for DID creation

[KendallWeihe]

Summary

This PR proposes the introduction of a web5 CLI tool. Originally prompted by #20 this ticket was inspired by the ftl command line utility.

By no means is the exact DX orthodox, I expect we'll iterate on this, but this puts all the basic pieces in place.

• cmd/web5/ Go package, which makes use of Kong (cc @alecthomas)
• scripts/web5 so that developers will instantly gain access to the web5 CLI once they activate their hermit environment
• Add scripts/ to the hermit env vars
• Add basic README instructions

Supported commands

• web5 did:jwk create
• web5 did:web create <domain>
  • example: web5 did:web create tbd.website

Both commands will print the full Portable DID (JSON formatted with indenting) to the terminal

➜ web5 -h
Usage: web5 <command>

Web5 - A decentralized web platform that puts you in
control of your data and identity.

Flags:
  -h, --help    Show context-sensitive help.

Commands:
  did:jwk create
    Create a did:jwk.

  did:web create <domain>
    Create a did:web.

Run "web5 <command> --help" for more information on a command.

Example did:web creation

web5-go on  kendallw/cmd-did-create [$] via 🐹 v1.22.0
➜ web5 did:web create tbd.website
{
  "uri": "did:web:tbd.website",
  "privateKeys": [
    {
      "alg": "EdDSA",
      "kty": "OKP",
      "crv": "Ed25519",
      "d": "lZZJnTGwkiJ0BXFdkjctG4ZoJJAxDUllpuSpv_zysI1bgLjFXU2S_3XOZQbTxPZg6RPTEHW_gTUfLykMrfufTA",
      "x": "W4C4xV1Nkv91zmUG08T2YOkT0xB1v4E1Hy8pDK37n0w"
    }
  ],
  "document": {
    "id": "did:web:tbd.website",
    "verificationMethod": [
      {
        "id": "#0",
        "type": "JsonWebKey2020",
        "controller": "did:web:tbd.website",
        "publicKeyJwk": {
          "kty": "OKP",
          "crv": "Ed25519",
          "x": "W4C4xV1Nkv91zmUG08T2YOkT0xB1v4E1Hy8pDK37n0w"
        }
      }
    ]
  },
  "metadata": null
}

---

Closes #20

[KendallWeihe]

Didn't want this PR to get too beefy so created the following follow-up items

• Add command line args for DID creation output (indentation & save to a file) #64
• Add web5 command for did:dht create #65

Edit: also added this one

• Build, publish and host the web5 CLI #66

[alecthomas]

Looks great to me!

[mistermoe]

awesome start @KendallWeihe