Export Raw Histogram Data If Possible

[zegelin]

Determine if it's possible to export raw histogram data as a Prometheus Histogram, rather than as a Summary.

This would allow for aggregation and other things.

[TvdW]

Hey, I'm interested this and after prototyping something I concluded that this would be very doable (had a test setup running for a few weeks and it produced some very useful data). If you haven't started work on this I'd be very happy to contribute a patch.

[zegelin]

Hi @TvdW, I haven't started work on this yet.

We'd be grateful if you were willing to contribute your patch.

[TvdW]

Pushed #90 which is a POC. Please have a look and let me know what you think.