[Feature Request] Validation: add explanation and show file in tree view

[Brilator]

The Validation feature and view is currently a bit confusing. One can add and save a validation, which then pops up in commit without being visible in the tree view. Plus, one might expect a "validate" button in that view and receive results.

Unless it is planned to incorporate validation into the ARCitect and display validation results, I would suggest to

• add a short explanation that the ARC is validated via DataHUB with the next synchronization (link to knowledge base articles)
• display the .arc/validation_packages.yml

[JonasLukasczyk]

If the feature to display the .arc folder as any other in ARCitect gets enough up votes I will add this.