discussion: remove the need for existing system dependencies

[merklefruit]

Currently the main README includes this paragraph:

First, make sure you have a few things installed.

- [Rust](https://www.rust-lang.org/tools/install)
- [Docker](https://www.docker.com/)
- [Docker Compose](https://docs.docker.com/compose/)
- [Make](https://www.gnu.org/software/make/)
- [jq](https://jqlang.github.io/jq/)

Ideally op-up should be able to be run on by everyone on a new machine.

A potential solution includes the use of a custom Nix environment. Never used this tool personally, so I'm also curious to learn and explore it for this use case.

A simpler solution is to just check if pre-requisites are installed (e.g. by using which x or x --version commands) and prompt the user to finish installing the ones that aren't yet on $PATH.

[refcell]

Haven't used custom nix environments either, and don't think it's highly adopted so imo the path of least resistance here would be to create an install builder with prompt-based installs for the required dependencies.

[merklefruit]

52 will add curl and tar as dependencies