image / basefiles: make console password configurable

package/base-files/files/etc/config/system

package/base-files/files/etc/inittab

package/base-files/files/usr/libexec/login.sh

package/utils/busybox/Config-defaults.in

target/linux/adm5120/base-files/etc/inittab

target/linux/ar71xx/base-files/etc/inittab

target/linux/arm64/base-files/etc/inittab

target/linux/brcm2708/base-files/etc/inittab

target/linux/ipq806x/base-files/etc/inittab

target/linux/lantiq/base-files/etc/inittab

target/linux/malta/base-files/etc/inittab

target/linux/mediatek/base-files/etc/inittab

target/linux/mxs/base-files/etc/inittab

target/linux/omap/base-files/etc/inittab

target/linux/omap24xx/base-files/etc/inittab

target/linux/ppc44x/base-files/etc/inittab

target/linux/ramips/base-files/etc/inittab

target/linux/realview/base-files/etc/inittab

target/linux/sunxi/base-files/etc/inittab

target/linux/x86/base-files/etc/inittab