chore(users): grfn -> aspen

Change-Id: I6c6847fac56f0a9a1a2209792e00a3aec5e672b9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10809
Autosubmit: aspen <root@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI
Reviewed-by: lukegb <lukegb@tvl.fyi>

users/aspen/web/shell.nix

@@ -0,0 +1,9 @@
+with import <nixpkgs> { config.allowUnfree = true; };
+mkShell {
+  buildInputs = [
+    awscli
+    gnumake
+    tarsnap
+    certbot
+  ];
+}