If We need to use it fast as every day action we need three things:
1. Option in host form:

2. Option in devices list form in dropdown menu:

3. Option in sites.php to add whole site to maintance by one click somehow (now+1h).
4. Option to set maintance mode for devices for specified branch from tree in monitor.php.
5. Show devices in maintance mode in monitor.php with other icon (or icon 'screwdriver' from font awesome on the top).
6. Enable/Disable maintance mode switch in device.php.
Something like this.
