Default values of the default values

[jacob-mannhardt]

In our current approach, we have to fill every attributes.json file with all parameters, most of which we probably never touch.

Can we simplfiy this, following our paradigm that we should only provide those values that we actually want to touch?

I see two options:

1. we can provide an attributes file for the group of technologies in the input data
2. we can provide the default values in the code (e.g., default demand is zero etc.)

The issue are the units but we can circumvent that by skipping that specific parameter of that specific tech/carrier in the unit consistency tests.

I think in general it should be possible to derive default default values

[jacob-mannhardt]

similar to default_config