nix configuration for my work mac

Largely based on examples from https://github.com/ryan4yin/nix-darwin-kickstarter/

my opinionated changes:

1. I still want a pretty minimal setup. I don't want a lot of packages installed that I'm not going to use. I don't want a lot of customizations to the environment (I prefer to keep it reasonably close to defaults).
2. I prefer nix to brew for managing packages whenever possible. The only brew installed stuff is packages that currently don't work right with nix.
3. I'm not really a big fan of home manager, and prefer other approaches to managing dotfiles, etc.

To use this:

• clone it
• make sure you have nix and homebrew installed (default instructions on the web should work for those)
• change the hostname in flake.nix and Makefile (mine is called aeon)
• change any settings in modules/system.nix or modules/apps.nix to your liking.
• run make deploy to install it.