Instructions to backup persistent data do not respect ownership of files

The instructions to manually copy persistent data to a new device
override the ownership of files owned by amnesia:amnesia to root:root.
This leads to unusable personal files.

A workaround could be to issue the following command after copying the
folders:

find /live/persistence/TailsData_unlocked/ -maxdepth 1 -type d -uid 1000 -exec chown -R 1000:1000 '{}' \;

Shall we ask the user to execute this command, or shall we find a better
way of solving that issue?

Feature Branch: doc/7216-persistence-backup-permissions

Related issues

• Related to #5301

Original created by @sajolida on 7216 (Redmine)