Split assets-data for new capacity and existing capacity

[gnawin]

What and Why

Currently, assets-data.csv includes data for both new capacity and existing capacity. However, for existing capacity, we only need a few parameters, in particular, we'll mostly use existing capacity for producers/conversions. This means we'll have lots of redundant columns for the existing capacity.

The proposal is to split assets-data further, similar to what was done before with groups-assets-data.

Furthermore, what may be considered is the split the data even more for different asset types, because now we have lots of columns that only apply to certain asset types, e.g., for storage. But this can be a different issue.

Possible Drawbacks

No response

Related Issues

No response

[datejada]

Update: After #781 the input value is initial units rather than existing capacity