Simplified tester onboarding

Description of the feature request

When testers are being onboarded they go through the same onboarding process as developers/admins.
Testers are in many cases non-technical users. The device registration process is not straightforward at all, and also there is no central list of available builds (and history) for testers.

Use case / for what or how I would use it

  1. When a test user clicks the invitation link in order to accept it, they should dive into their settings page to register their device. Since testers are here only to test builds, this should be done wherever they land, so they won’t have to go few levels deep into the structure.
  2. Other than received mails, there is no central location to download past builds. Currently they have to open the build and search for the artifacts.

Thank you for the feature request! :upside_down_face: