Support richier configs to bundle source images

[andrew-k-21-12]

Whatever types of raster source images are used, all of them are eventually bundled as WebP and PNG only. No compression configurations are provided. No animated formats are supported (most likely).

Consider updating the frontend-resource-wrappers plugin's APIs to:

1. Configure output formats of raster images.
2. Allow different configs on their compression.
3. Support image formats with animations.