Multiple zone 1 tests

[louisg-rte]

For cases where the topology type is “Multi”, there will be more than one type of generating unit, so Zone 1 tests must be performed for each of these units (which will typically have different models, or models with different parameterization). There is a need to modify the tool to perform "multiple Zone 1 tests", i.e. perform Zone 1 tests for each of the declared generating units. It would be nice if the tool checked whether Zone 1 cases are really different, warning the user when he is declaring units having identical models and parameters.

[jl-marin]

Additionally, we need to document whether there are any special precautions to take into account in terms of primary control, since here we are putting generators in parallel.