Simplify Froehlich_CellSystems2018 condition table (#293)

The current condition table for Froehlich_CellSystems2018 is unnecessarily large (37.2MB):

* There are 477 parameters that take the same value across all conditions, which is also the same value as already specified in the SBML model. Thus, drop the respective columns from the condition table.
* There are 16 parameters in the condition table that use the same value across all conditions, but a different value is set in the model. Update the value in the model and drop the respective columns from the condition table.

Author: dweindl