Give ColorEditor possibility to disable Alpha

In the QSR project, we have the need to have either fully transparent background by default or if the ColorEditor is used, then fully opaque color must be chosen.

Other possible solutions would be a opaque black default color (that can be changed to another opaque color) and a checkbox to make the background fully transparent with a warning dialog (that we can populate with a text).

Also workable solution is to just plain disable alpha from the ColorEditor and have the UI designer manually change the QML to have fully transparent background color with warning from our QtSafeLayoutTool.

(*)content verification by CRC checking requires that the non-safe content in HW background layer does not shine through to mess CRC calculation of Safety  Critical content in HW foreground layer.