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/achilles/shell.nix

@@ -0,0 +1,18 @@
+with (import ../../.. { }).third_party.nixpkgs;
+
+mkShell {
+  buildInputs = [
+    clang_11
+    llvm_11.lib
+    llvmPackages_11.bintools
+    llvmPackages_11.clang
+    llvmPackages_11.libclang.lib
+    zlib
+    ncurses
+    libxml2
+    libffi
+    pkg-config
+  ];
+
+  LLVM_SYS_110_PREFIX = llvmPackages_11.bintools;
+}