Add Orientation and Starter-Projects docs Bug: angleproject:1944 Change-Id: Idd1cf50a1751bf0d5a04159fffbc91a3225f9768 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1496038 Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org> Reviewed-by: Yuly Novikov <ynovikov@chromium.org>