[Task] Implement JSON-LD output format for DID Documents

## Description

Implement JSON-LD output format for DID Documents. Previous iteration of this Issue held more DID Core updates, but they have either been tackled or have their own issues right now.

## Resources

- [JSON-LD](https://www.w3.org/TR/did-core/#representations)

## To-do list
Create a task-specific to-do list . Please link PRs that match the To-do list item behind the item after it has been submitted.

- [ ] Allow output of JSON-LD (Aka, just add the default context)

## Change checklist
Add an `x` to the boxes that are relevant to your changes, and delete any items that are not.

- [ ] The feature or fix is implemented in Rust and across all bindings whereas possible.
- [ ] The feature or fix has sufficient testing coverage
- [ ] All tests and examples build and run locally as expected
- [ ] Every piece of code has been document according to the documentation guidelines.
- [ ] If conceptual documentation (mdbook) and examples highlighting the feature exist, they are properly updated.
- [ ] If the feature is not currently documented, a documentation task Issue has been opened to address this.