Introducing WindowConfiguration

Used to house configurations that don't affect resources and that
we don't want to communicate to apps, but need to be propagated
along side Configuration.

Test: bit FrameworksServicesTests:com.android.server.wm.WindowConfigurationTests
Test: adb shell am instrument -w -e package com.android.server.wm com.android.frameworks.servicestests/android.support.test.runner.AndroidJUnitRunner
Change-Id: I97de3efbe6d5e1d3b07156a8cfbce9be5eae5cb5