renderer_vulkan: Add setting to log pipeline statistics

Use VK_KHR_pipeline_executable_properties when enabled and available to
log statistics about the pipeline cache in a game.

For example, this is on Turing GPUs when generating a pipeline cache
from Super Smash Bros. Ultimate:

Average pipeline statistics
==========================================
Code size:       6433.167
Register count:    32.939

More advanced results could be presented, at the moment it's just an
average of all 3D and compute pipelines.