Compile JXL encoder

codecs/jxl_enc/example.js

@@ -0,0 +1,12 @@
+const fs = require("fs");
+const avifEnc = require("./jxl_enc.js")(fs.readFileSync("./jxl_enc.wasm"));
+
+avifEnc.onRuntimeInitialized = () => {
+  const jxl = avifEnc.encode(
+    new Uint8Array([255, 0, 0, 255, 0, 255, 0, 255, 0, 0, 255, 255]),
+    3,
+    1
+  );
+  console.log(jxl)
+  fs.writeFileSync("lol.jxl", jxl);
+};