CoreS3 refactored & remove M5 libraries (#143)

Remove dependencies M5Unified and M5GFX because:
- Sometimes the release doesn't even compile
- The amount of functions is too close to the limit (I recently had to remove some code/dependency to be able to make a build at all)
- Graphics performance issue since last update
- Touch screen performance issues (not perfect yet, but better)
- Compatibility issues with Tactility SPI/I2C versus M5Unified/M5GFX variants.

Boards/M5stackCore2/README.md

@@ -0,0 +1,11 @@
+# M5Stack Core2
+
+This board implementation concerns the original Core2 hardware and **not** the v1.1 variant.
+
+Reference implementations:
+- [ESP-BSP](https://github.com/espressif/esp-bsp/tree/master/bsp/m5stack_core_2)
+- [M5Unified](https://github.com/m5stack/M5Unified)
+- [M5GFX](https://github.com/m5stack/M5GFX)
+
+Docs:
+- [M5Stack.com](https://docs.m5stack.com/en/core/Core2)

Boards/M5stackCore2/Source/hal/Core2Display.cpp

@@ -12,7 +12,7 @@
 #include "esp_lvgl_port.h"
 #include "Core2Touch.h"
 
-#define TAG "yellow_display"
+#define TAG "core2_display"
 
 bool Core2Display::start() {
     TT_LOG_I(TAG, "Starting");