Add launch screen

quantum_launchscreen_contacts.xml files are generated by following
go/launch-screens

All added drawables are copied from:
java/com/google/android/assets/product/res/*/*.png
java/com/google/android/assets/googlelogo/res/*/*.png

All added dimens are copied from:
java/com/google/android/assets/launchscreens/res/*/dimens.xml

Bug: 30255034
Bug: 35360058

Test: on nexus 5x and 9, observe launch screen shown correctly.

Change-Id: If9a659b65ef9d0ea38b377b8ecdb5382314570f5