moved provider selection popup menu to be at the top of the main window

for now, i just removed the label that was in its place. i never found the label status to be very useful anyway.
Yes, "the Qt way" is the way @ivanalejandro0 mentions. The goal is to not handle callbacks, which is the main contrast with frameworks like Gtk.

This makes a lot of sense in C++, it may not so much on Python, but I would still follow "the Qt way".