WIP: CI preview backend integration

Ticket(s) / Related Merge Requests

#5360 (closed)

Summary of Changes

• Implemented a CI job that can be triggered from the backend to build preview apps
  • It fetches the tenant config and assets
  • Build the preview app
  • Calls a backend's webhook when with the result

Screenshots

(Any extra UI screens that can be shared)

Does this impact

• Localization
• Dark/light mode
• Guest mode