Architecting TM support

1. General:
- [x] We do JSON, JSON-LD, normal TM validation and probably additional check (need to restructure core package)
- [x] New assertion validation for TMs

2. Assertions Package:
- [x] Add 2 assertion folders and 2 list.json for TMs and TDs

3. CLI consideration
- [x] Add options for validating TM or TD
- [ ] Allow the user to specify additional schemas for validation?

4. Frontend (low priority)
- [x] Dynamically detect TD or TM etc...