Move non-AOSP values to vendor_xxxxxx.xml

When merging in new version of android, xml resources
tend to have a lot of conflicts due to changes and
additions we've made so need to manage those changes
better.  By using additional xml resource files we can
group our changes without modifying the current AOSP
resources.

PS2:
Switch to using a ROM agnostic vendor_xxxxxx.xml naming.

Change-Id: I11c8c29ea146f6e3cfe1fd452aafb6d3807f2983

Conflicts:
	res/values/strings.xml
Lock Screen - Add Lockscreen Wallpaper (2/2)

PS3 add Default Wallpaper as option

PS4 fix preference list doesnt show selected item

PS7:
Rebased and modified to check for existence of a lock screen
wallpaper when updating the preference.

Change-Id: I2f4db0ddc132482d191eea4f76160b51b4063a60