Added PRISMA mapping (based on ScenarioMIP)

[dbantje]

Purpose of this PR

This adds a mapping for the PRISMA project. The mapping is based on the ScenarioMIP mapping. For now, additional variables for material demands, material stocks, and scraps are not mapped.

Checklist:

• I did not use Excel to open csv files or checked that no side-effects occur (changed values, many new quotation marks, …)
• I added any renamed piam_variable to renamed_piam_variables.csv to guarantee backwards compatibility.

It is recommended to have a look at the tutorial before submission.

[dbantje]

@orichters , @fbenke-pik Can't assign reviewers here. Could you review this PR?

[orichters]

For the record: We added the Test line because mappings with no single piam_variable fail the tests in various ways.