Sensitivity Analysis: handle multi-dim variables and other types

Issue 1:

For multi-dim variables, the sensitivities are returned only for the first dimension.

• for inputML variables, return sensitivity for all dims
• for outputML variables (features).. ? either calculate for each dimension (the user can only provide the variable's name), and/or allow user to provide specific dimension (smth like varname_0 i.e. feature name with suffix)

Issue 2:

Sensitivites are now defined for DataReal and DataCategorical, but not DataInt and DataBool.