pkgs/http.server: Add shortcut command for python3 http.server

pkgs/http.server/default.nix

@@ -0,0 +1,14 @@
+{
+  python3,
+  writeShellApplication,
+}:
+
+writeShellApplication {
+  name = "http.server";
+  text = ''
+    python3 -m http.server "$@"
+  '';
+  runtimeInputs = [
+    python3
+  ];
+}