hwui: Allow to blacklist android applications

Add support for a local config folder with blacklisted process names
/data/local/hwui.deny/<package name>

Only enabled with "hwui.use.blacklist=true"

This system can be used easily from adb shell, without reboot
or with a setting app, like the one i use, HwaSettings

Change-Id: I436b5dd7d6bf9fd36be7e86fc9d2a174a66701ff