Add 'Neovim from Scratch' Tutorial

[cleong14]

Add ChrisAtMachine - Neovim from Scratch YouTube tutorial playlist to 'Existing tutorials for writing Lua in Neovim' README section.

• ChrisAtMachine - Neovim from Scratch (YouTube Playlist)
• ChrisAtMachine - Neovim from Scratch (GitHub)

[matu3ba]

stuff like NOTE make sure you have [node](https://nodejs.org/en/) installed, I recommend a node manager like [fnm](https://github.com/Schniz/fnm). is not necessary to use neovim. It should be mentioned, why the additional dependency is needed/what it is used for.

The biggest drawback of this guide is that 1. the repo has no structure of the different sections wrt added code and 2. it is not immediate to users what code has been added in each section + why/for which use case a particular plugin is relevant.

For example, I still use telescope with the default key-mappings and I dont see what a pile of mappings does teach the reader.
I could see how this is an example for a particular organizing of keymappings, but this idea does not get evident from reading the code in the repo.