Detecting NaN values before computation, even if not in the input file

[christophe-david]

Is your feature request related to a problem? Please describe.
FAST-OAD returns an error if an input file contains a NaN value for a used input variable, but launches the computation if the input file misses an input variable that has NaN as default value, leading to OpenMDAO stopping it computation after the first iteration because NaN are present in residuals.

Describe the solution you'd like
FAST-OAD should return an error if an input variable as NaN value, whether it comes from the input file or from the default value.