Implement UI scaling and more (#501)

**New Features**
 * Runtime font accessors and new symbol fonts for text, launcher, statusbar, and shared icons.
 * Added font height base setting to device.properties
 * Text fonts now have 3 sizes: small, default, large

**Improvements**
 * Renamed `UiScale` to `UiDensity`
 * Statusbar, toolbar and many UI components now compute heights and spacing from fonts/density.
 * SSD1306 initialization sequence refined for more stable startup.
 * Multiple image assets replaced by symbol-font rendering.
 * Many layout improvements related to density, font scaling and icon scaling
 * Updated folder name capitalization for newer style

Modules/lvgl-module/include/tactility/lvgl_fonts.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <lvgl.h>
+#include <stdint.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum LvglFontSize {
+    FONT_SIZE_SMALL,
+    FONT_SIZE_DEFAULT,
+    FONT_SIZE_LARGE,
+};
+
+const lv_font_t* lvgl_get_shared_icon_font();
+uint32_t lvgl_get_shared_icon_font_height();
+
+const lv_font_t* lvgl_get_text_font(enum LvglFontSize font_size);
+uint32_t lvgl_get_text_font_height(enum LvglFontSize font_size);
+
+const lv_font_t* lvgl_get_launcher_icon_font();
+uint32_t lvgl_get_launcher_icon_font_height();
+
+const lv_font_t* lvgl_get_statusbar_icon_font();
+uint32_t lvgl_get_statusbar_icon_font_height();
+
+#ifdef __cplusplus
+}
+#endif