* Add MDNS.addServiceTxt() to SimpleMDNS
Fixes#2678
A simple mapping allows for basic service text addition even when using
SimpleMDNS and ArduinoOTA.
* Protection against duplicate services addition
* Enable LWIP IGMP, MDNS internal server
* Enable MDNS lookup from LWIP DNS
* Add SimpleMDNS responder, small code and no malloc
* Ensure we copy out lwipopts in make-libpico
Adds a small wrapper around the LWIP-provided MDNS responder application.
Drop-in replacement in many basic cases for LEAmDNS.
For FreeRTOS it is important to not allocate memory on an LWIP callback.
LEAmDNS needs to do this to create response objects, leading to crashes.
Increase LWIP timers by bumping the LWIP_ARP number (as done before).
Replace ArduinoOTA LEAmDNS with SimpleMDNS and update a
HTTPUpdateServer example.
