Package alterator-multiseat: Information

- fix list-seats (closes: #39917, #39964)
- reboot when activate
- show drm/card0
- small fixes
- change message for pop-up dialog

- disable saving configuration
- hide /drm/card0
- fix popup message (closes: #39916)
- fix help

- disable test activation (closes: #39911)
- add multiple selection in the device list (closes: #39915)
- show a message box when activated (closes: #39916)
- flush-devices when remove seat (closes: #39913)
- rename buttons (closes: #39918, #39912)
- update help (closes: #39910, #39914)