Allow forecast boundary limits to be calculated

Our clients always have limited inventory to sell. What they sell is constantly changing. When forecasting future results, the prediction frequently projects results beyond the saleable inventory. Our clients a neighbor indicator widget showing the maximum capacity for the given product, and then edit the forecast hardcoding the value into boundary maximum limit. However, this prevents the widget from respecting dashboard filter changes that switch between products. Instead, it would be most helpful if the boundary limitations could also be configured as calculated values from the data.