feat: The Credential Server could be improved to make it easier to add new Schemas

[bkreiser]

Is your feature request related to a problem? Please describe.

There are a few hard coded Schemas with things like their SAID defined in numerous parts of the code. It seems to me that adding new Schemas should be done in one place; ideally in Configuration and not code. This would make it easier for developers to leverage this code base for their own requirements.

Describe the solution you'd like

Ultimately I think that their could be a database of Schemas and they could be added at Runtime. In addition, it seems that it would be fairly straight forward to autogenerate a form to edit the instances rather than having to develop custom code to edit objects of each Schema.

Describe alternatives you've considered

If the Schemas are to remain as part of the code, they don't need to be expressed in numerous files. I see the SAID's defined in a few places.

or

Alternatively, Schemas could be expressed in Configuration files that are loaded at runtime.

or

Ultimately, Schemas could be added through UX to extend the Credential Server.

Additional context

[iFergal]

We did some work in #1192 to remove the hard-coding in the UI files, but there's more work to do there to handle different types of fields or nesting of fields. And some work in the server.

We were exploring a schema builder in the UI to populate a database a while ago but de-prioritised it to focus on production features of the wallet - it could come back later. The tricky part is handling continuous nesting of attributes deeper and deeper into a schema. So could take a while before this enhancement is fully completed.