Inserting encrypted USB drive does not prompt for decryption

Originally created by @huertanix on #15767 (Redmine)

While training journalists on using Tails and transferring documents offline between Tails workstations with LUKS-encrypted USB drives, journalists assume something went wrong / didn’t work when they insert a working encrypted USB drive and no notification or prompt appears.

A side note: Even once I point out the drive on the Nautilus side bar, trainees almost always assume that the eject symbol is what they need to click in order to decrypt+mount, because that is the only thing resembling something clickable next to the drive name. They end up ejecting it instead and then have to start over by re-inserting the drive. It would be great to bypass having to deal with Nautilus and the confusion it causes.

UX recommendations:

• Show a prompt to decrypt+mount a drive immediately when it is inserted. Once the drive has been decrypted and mounted, open a Nautilus window showing the contents of the now-decrypted drive. Other Gnome-centric distros (Kali Linux) show a prompt once a drive is inserted to enter a decryption passphrase and mount the drive, not sure if this is a Gnome setting or something they custom-made, but Kali is FOSS and sharing is caring:
  

• Create a shortcut for each USB drive inserted, on the desktop, as macOS does, for example.

• Blocked by #15900 (closed)