Fix home-manager impurity and add brew configuration

modules/darwin/brew.nix

@@ -0,0 +1,43 @@
+{ config, lib, pkgs, ... }:
+
+let
+  checkBrew = "command -v brew > /dev/null";
+in
+{
+  environment = {
+    extraInit = ''
+      ${checkBrew} || >&2 echo "brew is not installed (install it via https://brew.sh)"
+    '';
+  };
+
+  homebrew = {
+    enable = true;
+    autoUpdate = true;
+    global = {
+      brewfile = true;
+      noLock = true;
+    };
+
+    brews = [
+      "aws-sam-cli"
+      "fabianishere/personal/pam_reattach"
+      "netdata"
+    ];
+
+    casks = [
+      "1password"
+      "visual-studio-code"
+    ];
+
+    taps = [
+      "aws/tap"
+      "homebrew/bundle"
+      "homebrew/cask"
+      "homebrew/cask-fonts"
+      "homebrew/cask-versions"
+      "homebrew/core"
+      "homebrew/services"
+    ];
+
+  };
+}