Ssp experiment adaptation

[jkCXf9X4]

Start of discussion to extend the ls-ref to SSP as well

Please look over the sugested additions and provide comments and sugestions for improvements

[pmai]

Note that since the experiment format is really supposed to be removed from fmi-ls-ref and moved to MAP COORD prior to release of fmi-ls-ref, most of the suggested changes should be handled in a MAP-COORD controlled separate repo going forward. (The fact that they are currently contained in this repo is just to have a place to retain this prior to MAP COORD starting up properly after the coming Modelica General Assembly).

I'd also note that there should be a clear split between the experiment format, which ideally should not have any FMI/SSP-specific things, and the layered standards applying the experiments to something, which should likely contain the specific things, e.g. in fmi-ls-ref for FMI usage, and in a hypothetical ssp-ls-ref for SSP usage.

E.g. it would seem suboptimal if there is a reference from the experiment setup itself to the SSD it is supposed to be applied to, as the same experiment can usefully be applied to multiple SSDs inside an SSP - so there might be potential to split that out.

But those and other discussions are likely best kept in MAP COORD once it properly starts up.