Improve monkeysign integration in Tails

Our initial integration of monkeysign is lacking in many ways (see parent ticket). We’ve evaluated GNOME keysign but it’s not an alternative to replace monkeysign with it. Thus we should put more work into improving monkeysign’s integration into Tails.

Before working on this, see #11240 (closed) that has updates about the future (or lack thereof) of monkeysign.

Parent Task: #6338 (closed)

Related issues

• Related to #11240 (closed)
• Related to #14581 (closed)
• Blocked by #8400 (closed)

Original created by @intrigeri on 8401 (Redmine)