feat(http_server): add 413 Payload Too Large response

While not useful for the HTTP parser itself, this is very useful for
memory-limited consumers of the HTTP server API.

Signed-off-by: Harshit Malpani <harshit.malpani@espressif.com>

components/esp_http_server/include/esp_http_server.h

@@ -608,6 +608,9 @@ typedef enum {
      */
     HTTPD_411_LENGTH_REQUIRED,
 
+    /* Incoming payload is too large */
+    HTTPD_413_CONTENT_TOO_LARGE,
+
     /* URI length greater than CONFIG_HTTPD_MAX_URI_LEN */
     HTTPD_414_URI_TOO_LONG,