Roadmap Cost Calculation

[Plutoberth]

This task has a few parts:

• Identify the required parameters related to costs (interest, opex, capex, for example), and write a small doc about each of them. This also includes a sensible default value and its source.
• Figure out a model for pricing, that factors in at least what the original model did. You can look at calculateScenariosAndCosts and calculateCosts for inspiration.
• Given a roadmap (which is a collection of scenarios for every year), figure out the costs for each year (like the costs part of the scenarios-output table). Some non-trivial calculations are needed, for example calculating the capex of new solar installations per year.

ℹ️ This is already partially implemented here.

[Plutoberth]

Closed by #30