sits_stats: Obtain statistics for all sample bands
Description
Most machine learning algorithms require data to be
normalized. This applies to the "SVM" method and to all deep learning ones.
To normalize the predictors, it is necessary to extract the statistics
of each band of the samples. This function computes the 2
of the distribution of each band of the samples. This values are used as
minimum and maximum values in the normalization operation performed by
the sits_pred_normalize() function.