[packages] shadow: add chage utility

Signed-off-by: Kyle Anderson <kyle@xkyle.com>

git-svn-id: svn://svn.openwrt.org/openwrt/packages@36546 3c298f89-4303-0410-b956-a3cf2f4a3e73
[package] shadow: rework Makefile

Signed-off-by: Luka Perkov <luka@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/packages@36547 3c298f89-4303-0410-b956-a3cf2f4a3e73