nl_NL locale: Correct the negative monetary format (bug 24614).

According to CLDR 35.1 and the bug report the correct monetary format
for negative amounts should be "EUR -1 234,56" while previously it was
"EUR 1 234,56-".

This patch does not change the thousands (grouping) separator.

	[BZ #24614]
	* localedata/Makefile (LOCALES): Add nl_NL.UTF-8.
	* localedata/locales/nl_NL (n_sep_by_space): Set to 2 (a space
	between the currency symbol and the minus sign).
	(n_sign_posn): Set to 4 (the minus sign after the currency symbol).
	* localedata/tst-strfmon1.c (tests): Add test data for nl_NL.UTF-8.