Externalize FOD usage in modules

[Frontear]

Current example I want to bring up is:

dotfiles/modules/home-manager/programs/cheat/module.nix

Lines 42 to 48 in 8dac4f4

	xdg.configFile."cheat/cheatsheets/community".source =
	pkgs.fetchFromGitHub {
	owner = "cheat";
	repo = "cheatsheets";
	rev = "36bdb99";
	hash = "sha256-Afv0rPlYTCsyWvYx8UObKs6Me8IOH5Cv5u4fO38J8ns=";
	};

This derivation will not auto-update, which can leave it very outdated for long cycles. In this particular case I honestly don't care much because I forgot I even had this command, but it does highlight a small problem with writing locked FODs within the modules: it's very easy to lose track of them.

This should be addressed before too many FODs end up in my modules, as updating them will become a complete hassle.