Add property to get the current profile's layer height
Add property to get the current profile's layer height

This will then be displayed in the profile selection menu.

Contributes to issue CURA-2723.

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