Fixes for esp32-arduino 3.0 (and add library.properties)

[egnor]

The newest release of the ESP32 core for Arduino (3.x) comes with some breaking changes. Among other things, the underlying ESP-IDF updated from 4.4 to 5.1, in turn updating mbed TLS from v2.28.x to v3.x, which has its own breaking changes.

In particular, mbedtlx_md5_{starts,update,finish}_ret were renamed to the same name without _ret, which affects this code. This change adds conditional #defines and should work on either version.

Also, the ets_printf logging utility seems to have gone away; I can't actually find its previous documentation. I replaced some calls with the documented ESP_LOGE macro.

Finally, per #34 I incorporated a library.properties file, without which it would be hard for me to test these changes.

[mathieucarbou]

FYI, the AsyncTCP lib also has to be updated.

I am maintaining since a few months now a fork which is more up to date, compatible with Arduino 2 and 3, and which is already used in many big projects around.

https://github.com/mathieucarbou/ESPAsyncWebServer

[egnor]

(so I should consider this branch defunct?)