Create GraphicsEnvironment for communicating with driver loaders

The GraphicsEnvironment class is given information during application
start, and makes it available to EGL/GLES/Vulkan loaders that don't
have easy access to the VM or to the application Context. Currently
only the driver path is handled, but the existing support for setting
library paths (for Vulkan extensions) and cache directory information
should move here.

Bug: 33531483
Change-Id: I4e4e7fb21f1bcc67122e9173514af5f18c063991
Merged-In: I5820d3d1301d5461e10706f551b268c54d4f8926