Implement M5Stack Cardputer + minor Tactility improvements (#331)

- Implement M5Stack Cardputer: display, SD card and keyboard
- `St7789Display` now supports a "gap" configuration
- `ElfApp` has improved errors

Boards/M5stackCardputer/Source/InitBoot.cpp

@@ -0,0 +1,10 @@
+#include <PwmBacklight.h>
+#include <Tactility/Log.h>
+
+constexpr auto* TAG = "Cardputer";
+
+bool initBoot() {
+    TT_LOG_I(TAG, "initBoot");
+
+    return driver::pwmbacklight::init(GPIO_NUM_38, 256);
+}