feat(flake)!: common home-manager settings

Automatically add the flake's overlays to `home-manager`'s `nixpkgs.overlays`
Split up `reo101-shell`
Upgdate `cheetah` to `23.05`
Some formatting

modules/home-manager/nix-general/default.nix

@@ -0,0 +1,28 @@
+{ inputs, outputs, ... }:
+{ lib, pkgs, config, ... }:
+
+{
+  imports = [ ];
+
+  options = { };
+
+  config = {
+    # Add flake inputs to $NIX_PATH
+    home.sessionVariables = {
+      NIX_PATH =
+        builtins.concatStringsSep
+          ":"
+          (lib.mapAttrsToList
+            (name: input:
+              "${name}=${input.sourceInfo.outPath}")
+            inputs);
+    };
+
+    # Use flake overlays by default
+    nixpkgs = {
+      overlays = lib.attrValues outputs.overlays;
+
+      config.allowUnfree = true;
+    };
+  };
+}