Stat should not be only on last chunk of data

[MiniPlayer]

USER STORY

Current behaviour: Stat are calculated using last chunk of data which can be only one point...
Expected behaviour: Stat should be calculated on all historiacal data or at least on a wider range than last chunk. One year for example. Maybe this should be configurable as for timeseries requests.

One example to do this efficiently would be to precalcul agregation in chunks while injecting and build functions to calculate final agregations on the fly using those when requested.

ACCEPTANCE CRITERIA

DEFINITION OF DONE

• Code builds without warnings (technical task)
• Code unit tested (technical task)
• Code is reviewed by a peer colleague
• Documentation updated (user story)
• Build pushed to demo server (user story)