base-files: rename ULA generation script

git-svn-id: svn://svn.openwrt.org/openwrt@35204 3c298f89-4303-0410-b956-a3cf2f4a3e73
ipv6-support: Rename enable-ipv6 UCI defaults

git-svn-id: svn://svn.openwrt.org/openwrt@35205 3c298f89-4303-0410-b956-a3cf2f4a3e73