Use HTTP method table from ESP-IDF's nghttp (#4900)

Fixes: #4884

* Use HTTP method table from ESP-IDF's nghttp
* Parse methods using IDF's HTTP method list
* Make example's loops to allow the CPU to switch tasks

libraries/WebServer/examples/HttpAdvancedAuth/HttpAdvancedAuth.ino

@@ -56,4 +56,5 @@ void setup() {
 void loop() {
   ArduinoOTA.handle();
   server.handleClient();
+  delay(2);//allow the cpu to switch to other tasks
 }