Introduces partially checked checkboxes for Effects. If an Effect
has an enabled by default function and doesn't have an explicit
value in the config file the checkbox is set to partially. If there
is a value in the config, this will be used.
Clicking on Default will return to the partially checked state.
So far only the built-in effects support the partially checked state
and also the mutual exclusive groups do not support the partial checked
(main reason: RadioButton doesn't support it)
BUG: 336045
REVIEW: 118658
99b5426a21