Bring back the stand-alone GUI window #81
Description
Just as @TomMaullin's done for SwE in NISOx-BDI/SwE-toolbox#46 let's bring back the SnPM GUI... it does nothing more than trigger use of Batch system, but still is easier than wading through the long menus.
One nuanced difference is that the 'Configure' is not a single menu option but many; hence there will need to be a drop down menu instead of a button for the first option.