Make the Unsafe Browser run by the amnesia user as a native Wayland application

This will allow us to implement some of the related issues in a safe manner.

Incidentally, this should fix:

The Unsafe Browser allows to retrieve the publi... (#15635 - closed) ⇒ we can re-enable the Unsafe Browser by default
Most of the linked issues

User research findings

During #18762 (closed), P1 and P3 enabled the Unsafe Browser "just in case" from the Welcome Screen because they were on a public network, even though there was no captive portal this time. The bad usability of captive portals lead people to expose themselves to #15635 (closed) unnecessarily.

Edited Oct 12, 2022 by sajolida

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