Add demosaic's "capture sharpen" option to quick access panel

[frivoal]

Is your feature request related to a problem? Please describe.
demosaic's "capture sharpen" option is great. Convenient access to it would be very handy. However, while currently many of demosaic's settings can be added to the quick access panel, "capture sharpen" is not one of them.

Describe the solution you'd like
Include "capture sharpen" in the list of things that can be added to the quick access panel.

[ralfbrown]

It's in fact a more general oversight/limitation - the checkbox widgets in the exposure module aren't available to be selected either. They are all created with dt_bauhaus_toggle_from_params.