Improve Segment Overrides counter in the Project Settings Usage tab

[khvn26]

In in the Project Settings Usage tab, the right-hand number should represent project.max_segment_overrides_allowed * len(project.environments). Right now it's just project.max_segment_overrides_allowed, which causes confusion:

[matthewelwell]

I think we should either break this down by environment in this screen, or move this limit to a new screen in the environment settings. To avoid having another screen just dedicated to limits, my preference is the former.