Latest ESP core and hardware related changes.

A new release; tested with ESP-core 2.0.2, and arduino IDE 1.8.20.

This release contains an important fix for the framebuffer length, and adds a settle time for the SPI bus before SPIFFS initialisation. This may help with some clone boards..

I also added the ArduCAM_ESP32S_UNO board (thanks @rdragonrydr)
And made some UI and documentation tweaks and fixes (thanks @ArminJo , @15498th , @timgates42 et al.)