Add support for overriding the background color of a Tool button
Add support for overriding the background color of a Tool button

Contributes to CURA-3577

hmflash/Cura,fieldOfView/Cura,ynotstartups/Wanhao,Curahelper/Cura,hmflash/Cura,fieldOfView/Cura,ynotstartups/Wanhao,Curahelper/Cura