Create CMakeLists.txt

[jojo2357]

This will allow users using CMake toolchains (like myself) to include this as a component.

For most, this may not be useful, but CMake is how I use Jetbrain's CLion to work with the ESP-IDF environment. This allows me to put the repo in my components folder, and import it automagically

[siara-cc]

Hi, will the presence of this file cause issues for Arduino or PlatformIO IDE users?

[jojo2357]

No, please refer to the AsyncTCP component or the ArduinoJSON component or even the main ArduinoESP32 component. They all have their own CMakeLists.txt and work with all the other toolchains because the file will be ignored if not required.