Implement FPS counter for LVGL

[kyvaith]

Describe the problem you have/What new integration you would like
Show FPS counter in LVGL screens
Please describe your use case for this integration and alternatives you've tried:
Optimize screens for best performance

Additional context

In raw LVG we can define #define LV_USE_PERF_MONITOR 1 to have FPS counter shown.

[clydebarrow]

You can simply add the define in your yaml:

esphome:
  ...
  platformio_options:
    build_flags: ["-DLV_USE_PERF_MONITOR"]  

[kyvaith]

Perfect