Fix esp-idf compatibility, add support for basic auth, add support fo…

[baycom]

…r CO2 sensor MH-Z19, add support for cgi style get parameters, add support for factory reset config, add support for sealevel pressure from height, add support for hostname / sensor id

In summary I made a lot of changes / fixes to the code and added some new features - hopefully there is something useful for you within it. Because I use only the built-in LED of the ESP32 board I was not able to use the color signaling and I commented out the ledc_set_color(aqi,(1-aqi), 0); in main.c. Should have made it as a config option.