Implement moving percentile algorithm

[gavv]

Add a class that implements moving percentile algorithm based on these excellent articles:

• Fast implementation of the moving quantile based on the partitioning heaps
• Better moving quantile estimations using the partitioning heaps

(Also feel free to suggest a better approach if you know one).

The new class can be named MovQuantile or MovPercentile. Interface should be similar to core::MovStats class, which implements moving minimum, maximum, and variance.

We also need unit tests, you can find example here.

This task is needed for #712.

[novertia]

Hi can I work on this issue

[gavv]

Sure, thanks!

[gavv]

Merged