OCaml Onboarding: Introduction to the Dune build system

I like OCaml, I spend most of my day to day though in Elixir and I think one of the things that's so nice about elixir is mix.

There's a handful of mix commands you learn when you get started and it's such a great experience. You can crack open erlang application structure and learn more if you want, but if you just want to `mix compile` `mix deps.get` `mix test` that's also fine.

When I first learned ocaml I watched this really wonderful series https://www.youtube.com/watch?v=MUcka_SvhLw&list=PLre5AT9JnK... (highly recommend if you are at all interested) and it's great for learning the language and tooling but it's all opam up until the end when some of it switches to dune.

I think wanting to provide more details about what's going on is nice too, but I think there's a place for "here's the commands you will actually need in your day to day"