New top-down parameters for a partial retrofitted BES

[HvanderStok]

To simulate a partially retrofitted BES, introducing new top-down parameters such as QBuiNoRetrofit_flow_nominal and THydSupNoRetrofit_nominal would be beneficial. These parameters could be utilized for further parameterization so that these subsystems are automatically designed for the non-retrofitted state of the building. All retrofitted subsystems would still use the parameters QBui_flow_nominal and THydSup_nominal of the actual building.

[github-actions]

Branch issue-78-New_top-down_parameters_for_a_partial_retrofitted_BES created!

[FWuellhorst]

Regarding naming discussion, another option would be to use _nominal and _actual, with _nominal referring to the old values and _actual to those which are "actually" applied in the simulation. However, I think some users may think _actual is referring to the dynamic variable and not the parameter. Moreover, if _nominal is not used for all cases as the nominal value of the simulation, this further confuse. Thus, let's stay with _design and _nominal. Either way, the documentation has to specify it clearly :)