[FR] aggregateSeriesLists function implementation

[marcuzh]

It appears that support for https://graphite.readthedocs.io/en/latest/functions.html#graphite.render.functions.aggregateSeriesLists a.k.a sumSeriesLists function has been merged into graphite-web late last year. SEE https://github.com/graphite-project/graphite-web/pull/2647

Would it be possible to implement this in CarbonAPI for feature parity?

[Civil]

Eventually yes, as currently carbonapi is rather far away from feature parity with graphite-web (I think currently we have less than 90% of all functions that are there in 1.1, but mostly everything that was in 1.0, however I need to calculate that properly).

Usually I rely mostly on PRs if you really want to implement the function, or every now and then I take several days to implement as much as I can myself, but in that case no promises on when I'll have time.