Ability for calculating moving average

We would like to calculate moving average over time window, not over number of rows (as i can do today).

The ideal solution would be implementing something similar to what Vertica supports:
https://www.vertica.com/docs/9.2.x/HTML/Content/Authoring/AnalyzingData/SQLAnalytics/CalculatingMovingAverage.htm

This is something we would like to be supported in the latest versions (7.x)