Rootless GPU Debug for GLES

This commit adds the ability to enable debug layers for OpenGL ES.

Similar to Rootless Debug for Vulkan, layers can be loaded from the
APK or base directory of selected debuggable applications.

Layers will only be loaded when developers opt-in via settings for a
target application.

A separate application can now be specified as an additional location
for layer discovery.

Example usage:

  adb shell settings put global enable_gpu_debug_layers 1
  adb shell settings put global gpu_debug_app <target_app>
  adb shell settings put global gpu_debug_layers layer1.so:layer2.so
  adb shell settings put global gpu_debug_layer_app <layer_app>

Test: cts-tradefed run singleCommand cts -m CtsGpuToolsHostTestCases
Bug: 110883880
Change-Id: I16df1951be0c06c80a445991e3e6d1636222b17b