Bring back the progressbar when loading the binary

[trufae]

The dialog that shows some progress while analyzing the app in background is gone because it was causing deadlocks and segfaults because of race conditions. But this can be reimplemented without causing any crash if done properly as a separate thread for the gui instead of the other way around. I just commented the code for maintainance and simplicity reasons, but i understand some binaries may take 10-15s to analyze and this can be confusing to the users

[trufae]

The reason for not bringing back the blocking progressbar is because r2 should be fully thread safe and the analysis must run in background without blocking the ui. so imho is better to not bringing it back, but having some feedback for the user will beg ood