Implement query spo-stake-distribution

[palas]

Changelog

- description: |
    Add `query spo-stake-distribution` command to obtain stake distribution for SPOs
# uncomment types applicable to the change:
  type:
  - feature        # introduces a new feature

Context

This PR solves this issue: #850

It currently requires a source stanza sinze it requires on new functionality in cardano-api introduced in this PR: IntersectMBO/cardano-api#598

DO NOT MERGE: The PR shouldn't be merged before the stanza is not required and removed.

Associated PRs:

• In cardano-api: Expose querySPOStakeDistribution query cardano-api#598
• In cardano-node: Add test for query spo-stake-distribution cardano-node#5932

How to trust this PR

You can check the test in IntersectMBO/cardano-node#5932. I would ensure that documentation is consistent and sensible, and the types for keys are correct.

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