value maps show aggregates for different time samplings
From the "value map" tab, it should be possible to choose
- aggregates (mean, max, ... -- see https://toar-data.fz-juelich.de/api/v2/analysis/#available-statistics)
- samplings (daily, monthly, yearly, seasonal, ... -- available input boxes for dates will change upon user's selection)
prototype 0:
- available aggregate is "mean" (if the user chooses 'None', the value map of the selected time is shown)
- available time sampling is "user-defined" (with this all requested time samplings can be produced)