Implement alternative scenarios infrastructure for the calculator.
This implements the necessary infrastructure to have alternative scenarios in the calculator. This is a proof-of-concept - I would like somebody else to take this forward such that it is fit for merging.
I've deployed temporarily to test-cara for @andrejh (see http://test-cara.web.cern.ch/calculator/baseline-model/result for an example of the baseline report).
It may be that we don't want scenario comparisons at all in the report. Happy to reject this prototype entirely in that case.
Link with #48 (closed)