[Task] Fix the issues with json file preparation and a few other issues

1. Buttons in the Reduction Configuration window is not working, like the two browse buttons under Grouping. Also, the refresh buttons in the Q-range and r-range section is not working. I checked the previous version and they seem to be working fine so I suspect it should be something to do with the adding in of the scroll bar.

2. In the Merging entry of the json file, there should be a QBinning entry whose value should be in the format of a list, e.g., [0.0, 0.005, 40.0]. The value should come from the Q-range section in the Reduction configuration window. The value are Qmin, Qbinning and Qmax, respectively.

3. Again for the Merging entry, there is a Grouping sub-entry where we have Initial and Output sub-sub-entries. For the Initial one, we need to go back to the Reduction Configuration window - if From calibration file is selected for Intermediate, then the value for Initial should be the full name of the calibration file (see bullet point 4 below). If Browse is selected and file is specified through browsing, then the Initial value should be the browsed file name. The same logic applies for the Output sub-sub-entry.

   Here is an example group file that can be imported by browsing, for both initial (i.e. Intermediate) and output grouping, outputgrouping.xml

4. Concerning the calibration file, it can be imported from the Calibration browse button under the main table view. Here attached is an example calibration file that can be imported, NOM_144974_2020_06_04_shifter_cycle.h5.