Summary results in AS Hegemony API

[emileaben]

I'd like the ability to show AS Hegemony results over longer time periods. For this an API end-point that has summary results would be very beneficial.
So for hegemony scores over time (for an AS pair for example) the API would show the min/avg/max, and some indication if there was a hegemony score at all and/or for how much of the time (number of samples in that time period?)