[Feature Request] Some optimizations and lazy loading of images

[theKAKAN]

A list of things that we can do:
JS:

• Load Prism.js separately, preferably from a popular CDN. This increases a chance of hitting a cache.
• Don't load Prism.js unless there's some code (or load it as async/deferred)

CSS:

• Load fonts from a popular CDN cache instead of bundling it in.

Images:

• Adding loading="lazy" to image tags might be better.
• srcset attribute for <img> is now well-supported by most modern browsers, and we can have both src and srcset as a fallback.
• Convert images to WebP when hugo builds the server files. I imagine this would be required for implementing srcset as well, so might as well do it...

For the images part, there seems to be a well-made hugo module available: https://github.com/hugo-mods/lazyimg
A resource on srcset with hugo would be: https://cconcannon.medium.com/hugo-shortcodes-to-process-your-images-4f66c1d9a91b

I host my instance at kakan.omg.lol, however, I receive a score of around 80 because the images served are too big. It's my fault, but this would still be very good to see added! :)