Replace JSONObject type with JsonDocumentObject

[amonsosanz]

This PR replaces the type JSONObject with a new type JsonDocumentObject for all the data that can be serialized and parsed as valid JSON, such as queries or credentialSubjects.

The issue with typing serializable documents as JSONObject is that this type includes object as a valid value:

type JSONObject = {
  [x: string]: string | number | boolean | object | Array<object>;
}

object in TypeScript is very broad (basically any value that is not a primitive is an object). This includes functions for example.

This broadness makes it very hard for the clients of this library to parse data that adheres to types using JSONObject, such as the AuthorizationRequestMessage's did_doc.

[volodymyr-basiuk]

LGTM

[Kolezhniuk]

I'm ok with changes, but not sure should we rename JSONObject -> JsonDocumentObject. Can't we just preserve JSONObject to prevent others users of sdk change type?

[vmidyllic]

I'm ok with changes, but not sure should we rename JSONObject -> JsonDocumentObject. Can't we just preserve JSONObject to prevent others users of sdk change type?

as I see JSONObject still exists, so no problem