Stealth: Asset Optimizers

[cookiengineer]

The stealth/Request implementation uses a separate optimize event, which is reserved for asset optimizers. The idea is that asset optimizers compress image, audio, and video streams so that sharing them further will lead to a more efficient bandwidth experience.

This is more of a story because it needs several Optimizers to be written and integrated for multiple libraries and tools. As of now this seems to be a longer effort, as most of the necessary libraries haven't been ported to nodejs and require either offering bindings via neon-bindings or require porting/rewriting the underlying libraries to rust, too.

• Integrate optipng for .png files.
• Integrate libjpeg-turbo for .jpg` files.
• Automatically convert bmp and tiff files to jpeg.
• Automatically convert mp4 or mkv files.