Add external domain metadata interface

[radovanjorgic]

Description

This PR adds export of theExternalDomainMetadata interface and all of its types.

Connected Issues

https://app.devrev.ai/devrev/works/ISS-263582

Checklist

• Tests added/updated and ran with npm run test OR no tests needed.
• Ran backwards compatibility tests with npm run test:backwards-compatibility.
• Code formatted and checked with npm run lint.
• Tested airdrop-template linked to this PR.
• Documentation updated and provided a link to PR / new docs OR no docs needed.

[B-Lorentz]

Largely LGTM, was this generated by a deterministic tool from the jsonschema, or by AI?
It would however be helpful to have some tests, that show that the data accepted by these type declarations is the same as by the schema, and the other way around

[radovanjorgic]

Largely LGTM, was this generated by a deterministic tool from the jsonschema, or by AI?

This was generated by AI. I tried using some tool like json-schema-to-typescript, but AI version was muche better from all perspectives: size, readability, naming and so on.

[ftopic]

There are some things that we shouldn't expose since they are deprecated but otherwise LGTM

[gasperzgonec]

You're missing a json file in the root of the project, that makes the tests fail.