Print render-related stats in build output

[donmccurdy]

Currently this plugin follows the vite/rollup practice of logging build artifacts in stdout, with file sizes, in a format like this:

dist/a.glb                0.28 MiB
dist/b.glb                0.51 MiB
dist/c.glb                0.51 MiB

It'd be nice to see more render-related stats than this, including:

• draw calls
• vertex count
• texture memory

This could help to spot when the application slips under performance budgets, beyond just file size.