Historically GPU service lives in SurfaceFlinger as a convenient hack.
Howerver, SurfaceFlinger doesn't need to know about anything specific about GPU
capability, and shouldn't know about anything about GPU. This patch moves GPU
service out of SurfaceFlinger.

GPU service is a service that accesses to GPU driver, queries GPU capabilities
and reports back. Currently we use this information in CTS and some benchmarks.

BUG: 118347356
Test: Build, flash and boot, use `adb shell cmd gpu vkjson` to verify
Change-Id: I007989e0f3f73b5caf80277979986820dd127c32