Move Vulkan layer path setup to ApplicationLoaders

ThreadedRenderer was never the right place for this anyway, and
ApplicationLoaders can provide both the full library search path (not
just the extracted native library dir) as well as the application loader
namespace.

Bug: 28213888
Change-Id: Ibcc0a9178da4dba6f3f3105932fdac1a1d0261af
7 files changed