Deploy a platform for automated testing

Allow Tails core developers to run, on our infrastructure, the Tails automated test suite on ISO images that are already being automatically built there.

Parent Task: #5288 (closed)

Related issues

Blocks #6565 (closed)
Blocked by #7631 (closed)

Original created by @intrigeri on 6564 (Redmine)

To upload designs, you'll need to enable LFS and have an admin enable hashed storage. More information