Allow extended apps to change package name

For the added flexibility of allowing apps that extend from settings to
have a different package name, these instances of com.android.settings
as a xmlns need to be replaced with res-auto (which subsitutes the
package name at build time).

Bug: 174264676
Test: manual (sdk_gphone), make -j20 SettingsRoboTests
Change-Id: I03acda25dbf4d028cc73b77f41ad5dedca110ecb