refactor: split common/nixos.nix and -/home.nix

Split these big files into modular files that
are easier to share and read on their own.

profiles/common/home/fuzzel.nix

@@ -0,0 +1,14 @@
+{ ... }:
+{
+  programs.fuzzel = {
+    enable = true;
+    settings = {
+      main = {
+        layer = "overlay";
+        lines = "10";
+        width = "40";
+      };
+      border.radius = "0";
+    };
+  };
+}