Allow user to turn on/off maintenance mode for cloud.

[#67379218]
Renamed maintenance? method to admin_maintenance_in_progress?

maintenance? can confuse, because it says if application is in admin
maintenance and this is not the same as user maintenance.

[#67379218]
Merge pull request #134 from shellycloud/67379218-maintenance-mode-on-demand

User should be able to turn on/off maintenance mode for cloud