Improve Average function in reports with two or more levels of grouping

When you have a group in the reports module and choose average, the group will give you an average for all the items underneath and then there's an average for the overall items at the bottom. However, if you add a grouping layer the average for the top group, becomes the average of the sub-group average. It's not weighted, it's just the same calculation as done when you just have one group. This might not seem like a major issue, but it can be easily misunderstood for those reading the reports. For future reference, the request ID is: CR-384060.