LVGL add support for PNG images

[s-hadinger]

Description:

Add support for PNG images in LVGL with the help of lv_lib_png and LodePNG:

• support for PNG images in file-system or flash, without pre-conversion required
• enabled with #define USE_LVGL_PNG_DECODER (enabled by default with LVGL)
• enabled LVGL error logs

Example:(warning, due to the size of the image 320x240, this example only works with PSRAM, like M5Stack Core2)

Upload Sunrise320.png to the filesystem: right-click on the image below and save it.

sunrise = lv_img(scr)
sunrise.set_src("A:/Sunrise320.png")
sunrise.move_background()

Here is the result:

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works on Tasmota core ESP8266 V.2.7.4.9
• The code change is tested and works with core ESP32 V.1.0.6
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass