Add mask file input to the settings of the Engineering Diffraction GUI and use in the calibration and focus tab #38963
Description
Describe the feature
When calibrating each detector of an instrument it is possible for the calibration to fail for a given detector.
In the engineering GUI we load such a so-called whole instrument calibration in the settings, but at present it will use the uncalibrated DIFC of the detectors failing the calibration. This is typically OK if the fraction of pixels for which the calibration failed is small, but it is also possible for detectors to break in such a way that gives spuriously high counts.
This feature would add a mask file to use to specify pixels (broken/uncalibrated) to be ignored in the focussing