Fix bug for aggregating calculations in heatmaps

[metemaddar]

Previously the calculation was done before finding parents. This was a problem in resolutions below 10 to have some different values per hexagon. At generation of geojson, only the last value was applied to the result.

[metemaddar]

Now the process of finding parent is before doing calculations. So the calculation is now done per parent (Target resolution).

The problem now is that the parenting function, became a tight bottle neck. Because previously we ran the parenting on unique grid_ids, And now we run it on the input data. The performance of parenting is improved by using a cache (~25%). But it's still a bottle neck.

At largest request example, it takes around 5 seconds to run parenting.

[p4b-bro]

This task/issue closed on Tue Jun 06 2023 ✅