Add VINTF manifest for android.system.keystore2

A VINTF manifest is required for services that expose VINTF stability
interfaces. Now that libbinder_rs supports stability, we need to update
this usage.

Test: m && adb shell start keystore2
Bug: 179907868
Change-Id: I9d3b363c6315bace145385867a5c495bb9051870
3 files changed