Add some ToJSON instances needed by cardano-node

[neilmayhew]

Description

These are currently orphan instances in cardano-node but belong in ledger.

Closes #3418

Checklist

• Commit sequence broadly makes sense and commits have useful messages
• New tests are added if needed and existing tests are updated
• When applicable, versions are updated in .cabal and CHANGELOG.md files according to the
  versioning process.
• The version bounds in .cabal files for all affected packages are updated. If you change the bounds in a cabal file, that package itself must have a version increase. (See RELEASING.md)
• All visible changes are prepended to the latest section of a CHANGELOG.md for the affected packages. New section is never added with the code changes. (See RELEASING.md)
• Code is formatted with fourmolu (use scripts/fourmolize.sh)
• Cabal files are formatted (use scripts/cabal-format.sh)
• hie.yaml has been updated (use scripts/gen-hie.sh)
• Self-reviewed the diff

[neilmayhew]

@Jimbo4350 suggested I add some golden tests to make sure nothing breaks, so I'll do that next

[neilmayhew]

The golden tests I've added are the same as the ones I added to node in IntersectMBO/cardano-node#5772. I'm assuming that the ones there will be discarded after being used to check the upgrade after integration. They pass with the instances that are currently in node, so they will verify that nothing has changed.

[lehins]

Looks good. Thank you.