Multivariate functions

Implements non-scalar fields to support multivariate functions natively.

I tried to adapt the existing multivariate functions accordingly, but am not always sure, if I did this correctly. Could you please have a look into the changes to funcs.drift, funcs.outliers and funcs.scores @luenensc ? I am especially unsure about funcs.drift.flagDriftFromScaledNorm.

I want to point you to the behavior of the new, now explicit src-target workflow with multivariate functions. Currently, if a multivariate functions specifies a target, we:

• mask all fields, but not target, even if it exists
• squeeze the History of target, but not the Historys of the fields

Do you think this is alright @palmb and @luenensc ? Or should we rather also mask target and squeeze the fields? -> Questions resolved today's stand up, we stick to the implemented behavior.