add esp-idf tooling

esp-rom-elfs.nix

@@ -0,0 +1,21 @@
+{pkgs}:
+pkgs.stdenv.mkDerivation rec {
+  pname = "esp-rom-elfs";
+  version = "20241011";
+  src =
+    builtins.fetchurl
+    {
+      url = "https://github.com/espressif/${pname}/releases/download/${version}/${pname}-${version}.tar.gz";
+      sha256 = "sha256:1ag9z459pgr7rmjxqfl8a6mayjiqffqmbvmzixicf8d4ch0h07wj";
+    };
+
+  preferLocalBuild = true;
+
+  dontUnpack = true;
+
+  installPhase = ''
+    mkdir -p "$out"
+    cd "$out"
+    tar -xf $src
+  '';
+}