Prevent inconsistent status bar progress reporting states
This code was separated from !783 (merged) for easier review.
Merge setting title and progress percent into one method. This makes sure that the method can be called from all over the place and will still always show a consistent state instead of partially showing the progress percent for one progress but the label for a different one.
This is to enable various tasks reporting progress at the same time in a way that doesn't lead to a confusing mess for users. Usually multiple tasks do not show progress at the same time, but when it happens this commit should make sure that the user experience is at least bearable.
Allow not having a "Stop" button next to the progress report for tasks that cannot be stopped.