[WIP] Initial test of snippet

[barryvdh]

This is just a proof of concept to implement https://github.com/Yoast/YoastSEO.js

I had some trouble compiling the SCSS from the package, so copied that manually.

Not sure how to best integrate this. It's a lot more extensive, but that needs the 'article content' of the page, which I'm not sure how to detect. In the current form, you can just go to kupo.app/snippet?url=http://mysite.com and get the preview from the snippet.

Also, compiling with yarn doesn't work, only in watch mode :/ Due to error in YoastSEO