Add simple benchmarks for asset loading

## What problem does this solve or what need does it fill?

Asset loading speed is important for user experience, even if

## What solution would you like?

Add benchmarks for loading each supported type of asset.

## Additional context

`ogg` seems to be particularly slow to load.

As we replace and modify our audio and asset parts of the engine, having even simple benchmarks will give us a sense of where we need to focus improvements, and if the changes we make are helpful.