Evaluate tails-greeter revamp proposals

Someone with HCI skills should review and evaluate the mockups proposed to revamp the Tails greeter.

Blueprint: https://tails.boum.org/blueprint/greeter_revamp_UI/

Parent Task: #5464 (closed)

Related issues

• Blocked by #6418 (closed)
• Blocks #5319 (closed)

Original created by @intrigeri on 6417 (Redmine)