Description

Closes #798.

I want to change the name of at least one of the structs. If you have any suggestions I'm all ears.

Changes

1. Allow for us to get an UnsignedTransaction with witness data.
2. A small refactor where I changed the name of the validation types.
3. Add functions that take a sequence of inputs and outputs identifiers, does validation on the associated requests, and creates the associated sighashes.
4. Added stubs for logic that still needs some doing.

This PR does not implement any "cascading" of an invalid transaction to child transactions in the chain. That's still todo, but probably not in this PR.

Testing Information

This still needs some tests, hence the draft status, but it is ready for review.

Checklist:

• I have performed a self-review of my code
• My changes generate no new warnings
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules