Add offline CLI commands to maintenence

[mmattel]

Fixes: #887 (Purge-Revision CLI)

• Make the maintenance page devided into offline and online command sections.
• Add storage path explanation
• Add 3 CLI commands
• Move the reset pwd command into the offline section

No backport!

[mmattel]

Backport update: because this got added to 5.0.6, we need to backport to 5.0