perf(imageproxy): do not set cookies to image proxy so CDNs can cache images (#3332)

CDNs such as Cloudflare bypass their cache if cookies are set in the response.
clearCookies
middleware removes the header before imageproxy serves the image.

server/middleware/clearcookies.ts

@@ -0,0 +1,6 @@
+const clearCookies: Middleware = (_req, res, next) => {
+  res.removeHeader('Set-Cookie');
+  next();
+};
+
+export default clearCookies;