Build a multivariable table file in csv format
f_csv_multivar(files, daily = TRUE, fileo = "fileo")
A csv table, where the first field is a date and the next fields values
list of hts files
default = TRUE
name of the output file (without extension)
P. Chevallier - Jan-Feb 2022
The function build a cvs file with values extracted from several hts files at the same date. So, it's better to run `h_common` before to apply `f_csv_multivar`
If daily is TRUE, only the date is taking into account, not the time.