Start of configuration tutorials

I've updated the notes site with some configuration tutorials, which are still a work in progress. The configuration tutorials are designed with a philosophy of knowing what each line of your config files do, so the next time you read your config, it'll be easier to modify it. The tutorials are organized into different "levels", where each higher level adds more sophisticated functionality to the tool.

For this month, the intro and level 0 pages for tmux are fairly done. The other three levels are still a work in progress.

On the side, I've also been learning some web development with the goal of unifying the blog site and notes site to use a single SSG. I'm considering either using Astro or just sticking with Zola.