completely redo the external app ui

the label was weirdly cut off before, though admittedly I'm not sure
why, I do dislike grids though, so I'll happily blame the layout.

- there is no reason why the label should be squeezed. we put actual
text inside, eliding it makes no sense whatsoever. use qlabel instead
- instead of laying out in a grid, lay out as a column with the
pushbutton getting pushed to the left by a spacer in its row

the end result is the same layout but the text no longer gets cut off