Use python setup script to eliminate duplicated logic in Windows installer

Currently, we have a `setup` python script, that does all of the nitty gritty for setting up / configuring KA Lite.  This logic is mostly duplicated (though now some differences, due to age) in the Windows installer.

This PR calls into the `setup` script, instead of duplicating the logic.  Parameters are passed there, such that the GUI is used to gather data, and then they are passed to the python script to do the work.