Warn against plugging a Tails device in untrusted systems

Like mentioned by intrigeri in #7073, users shouldn’t plug their USB stick / SD card in computers running untrusted operating systems, because they could corrupt the tails installation. I think there should be a warning about this in the documentation.

Feature Branch: doc/7076-plug_untrusted

Related issues

Related to #9116 (closed)
Related to #11102

Original created by @segfault on 7076 (Redmine)

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