[FEATURE] - Add support for registering scripts as DReps.

[CarlosLopezDeLara]

What

Add support for registering scripts as DReps.

Expand cardano-cli conway governance drep registration-certificate so that it can also take --script-file and --script-hash as inputs.

The new flags should be alternatives to the existing --drep-verification-key, --drep-verification-key-file, and --drep-key-hash

The resulting certificate must comply with the conway cddl, where:

reg_drep_cert = (16, drep_credential, coin, anchor / null)

drep_credential = credential

credential =
  [  0, addr_keyhash
  // 1, scripthash
  ]

Why

From CIP1694

Registered DReps are identified by a credential that can be either:

A verification key (Ed25519) A native or Plutus script

Personas

• [ ] SPOs
• [ ] dApp Devs
• [ ] Exchanges
• [ ] Wallets
• [ ] 3rd party tools
• [x] ADA holders
• [x] DReps

Definition of Done (DoD)

• [ ] Acceptance Criteria + User Stories & DoD created and singed-off (by PO, dev & test owners)
• [ ] Builds successfully on CI
• [ ] Code & Test review (as per Acceptance Criteria)
• [ ] There is documentation and/or examples for the new functionality (usage/response)
• [ ] Log/record changes on Vnext (or similar depending on what we adopt)
• [ ] Ticket number(s) included in PR description
• [ ] All Acceptance Criteria met and covered by dev/unit/property/integration tests
• [ ] System/E2E automated tests + System Test Engineer Owner Sign-off

NOTE: Ideally, we should merge only fully implemented and tested features into the master branch. So all the above steps are required for the PR to be merged.
In order to avoid the PRs becoming stale and requiring to be rebased on master, these can be merged after a reasonable time (current agreement is 3 days) if the System Test Engineer Owner's sign-off was not provided (last step in the DoD).

IMPORTANT: Any deviation from the plan should be discussed and agreed as a comment in the Feature file.

Sign-off

• [ ] Product Owner
• [ ] Dev Owner
• [ ] System Test Engineer Owner

Related PRs

1. PR # here

Acceptance Criteria

[carlhammann]

We'll also have to make sure that the filtering by DRep credential done in the drep-state and drep-stake-distribution queries works with scripts and keys.

Edit: I opened an issue: #562