Introduce a function to return the expected average number of stories for a taxonomy string
The function should return the number of stories if exactly specified, the average value if a range is given (e.g. HBET:3-7 results in 4.5), or one more than an open range (e.g. HBET:8+ results in 9). Alongside this function, another function should deliver the minimum and maximum values of number of stories (equal if the number is exactly specified) to be used in Finalizer for reducing the assets based on number of stories.