Adopt the Nonius HTML reporter for benchmarks

[jalfd]

Embedding the Nonius benchmarking library has been extremely helpful, but one feature was left out (as far as I can tell).

With nonius, it was possible to specify -r html on the command line to enable the HTML reporter. This would generate some very nice graphs of the resulting benchmark data.

It would be great if that feature was also ported over from the Nonius library.

[amitherman95]

Sounds interesting I'd like to work on this, guys

[JoeyGrajciar]

@amitherman95 sure go ahead Output should not be just about benchmarks.

[horenmar]

Thanks to the new multi reporter support, the benchmark reporter doesn't have to handle non-benchmarking events.