changes all environment variables to be prefixed with DA_
adds the --country-whitelist command-line option to pass a list of the only countries you want to consider sellers from (i.e. to restrict to certain countries for shipping prices), + associated environment variable
DA_--country-whitelistcommand-line option to pass a list of the only countries you want to consider sellers from (i.e. to restrict to certain countries for shipping prices), + associated environment variable