Minimal changes to use the progress bar from the mainwindow instead of a floating widget.
However, it remains a ugly hack. One thing I really dislike is that I had to pull in a dependency to libkstapp.
As Peter said previously, we'd need to rework a couple of things...
But before we make any further changes, I think we need to work out a plan how we want to do it!

One interesting thing is that the configuration of an ASCII file leads to reparsing the file each time a setting is changed. Not
ideal when the parsing takes a long time. This is clearly visible now, and I think we need to fix this!