no_transform: Identity transformation and center/scale transform
Description
Perform an identity transformation. Admittedly it seems odd to
have a dedicated function to essentially do I(x), but it makes sense to
keep the same syntax as the other transformations so it plays nicely
with them. As a benefit, the bestNormalize function will also show
a comparable normalization statistic for the untransformed data. If
standardize == TRUE, center_scale passes to bestNormalize instead.