Setup the global variables for the various extract functions

setup_global_variables(
  dat_flag,
  data_dl_method = "libcurl",
  metadata_dirname = "metadata"
)

Arguments

dat_flag	(character) : name of the data - will appear as data folder name when data are saved
data_dl_method	(character) : "libcurl" (default) data download method
metadata_dirname	(character) : "metadata_dirname" (default) metadata folder name