[2/2] Navigation ring targets customization

Add navigation ring customization that allows up to three
targets on the navigation ring with custom shortcut actions.

[2/2] 个性化导航圈目标

添加个性化导航圈目标: 允许至多三个指向自定义快捷方式的导航圈目标.

[1/2] in platform_frameworks_base

Thanks to AOKP & CyanogenMod for the original implementation.
感谢AOKP & CyanogenMod原创实现此功能.