Add hash validation and support for HTTP(S) and IPFS to command hash anchor-data

[palas]

Changelog

- description: |
    Added hash validation and support for HTTP(S) and IPFS to command `hash anchor-data`
  type:
  - feature        # introduces a new feature

Context

This PR is a first step towards solving: #882
But it doesn't completely address it because the check should be in the commands mentioned and not in a separate command. That will be addressed in a separate PR.

How to trust this PR

The tests should provide a lot of assurance. I think the most unverified bit is the URL structure for IPFS_GATEWAYS, but I have tried it against existing gateways and seems to work. Other than that, code style, and maybe code organisation? We may need to move the verification code somewhere else in order to be able to use it in the next PR.

The PR adds quite a few packages, but it was mainly for testing. For querying it uses http-client (and http-client-tls for HTTPS support).

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated. See Running tests for more details
• Self-reviewed the diff

[carbolymer]

Nice! Quite elegant solution.

[Jimbo4350]

LGTM 👍 . Couple of comments and have somebody from devx look at your nix changes.

[angerman]

LGTM