Create EICs for standards after peak detection

[jorainer]

Create EICs for all standards for which a chromatographic peak was identified (in QC samples). Goal is
a) check if the signal from QC samples for that peak is somewhat comparable across batches: boxplot for intensity of peaks for a feature per batch.
b) check if the rt of these differs across batches.

[jorainer]

This should ideally be done in a separate file because it is supposed to take quite some time.