Document checking the file system of the persistent storage using the command line

As pointed out in #8169 (closed), it’s not possible to check file systems in Disks anymore. GParted is no option either. So let’s do this on the command line:

fsck -y /dev/mapper/luks-xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxx

While doing this we should create a “Persistence” subsection in “Advance topics” and move there:

• persistence/change_passphrase.mdwn
• persistence/copy.mdwn
• persistence/check_file_system.mdwn

Feature Branch: doc/10799-check-filesystem

Parent Task: #8043 (closed)

Related issues

• Blocks #8045 (closed)

Original created by @sajolida on 10799 (Redmine)