deprecate `flagByStray` and `flagMVScores`

Can we deprecate those 2 functions as well somehow? (Although part of the SaQC publication?)

Pro deprecation:

• flagMVScoers is a hard to use monolith that requires an exhausting parameter calibration process, especially for the selection of the transformations for the different variables included
• flagByStray has hard to interprete parameters
• not really used
• multivariate kNN scores as calculated in flagMVScores still can be calculated via assignkNNScores
• flagging of the scores via flagByStray (as it is hard coded in flagMVScores), though statistically elegant, does not really perform that good and is opaque in its results. Scores can be capped with any other Outlier detection algorithm as well
• removal slimlines the outlier detection library further to algorithms we know and maintain

Con deprecation

• part of the SaQC publication, maybe a bit hard to argue getting rid of it

Or maybe we can remove any documentation hintings too it, but keep it in the catalogue? Any thoughts on this @palmb @schaefed ?