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

Platforms/platform-esp32/bindings/espressif,esp32-spi.yaml

@@ -0,0 +1,38 @@
+description: ESP32 SPI Controller
+
+include: ["spi-controller.yaml"]
+
+compatible: "espressif,esp32-spi"
+
+properties:
+  host:
+    type: int
+    required: true
+    description: |
+      The SPI host (controller) to use.
+      Defined by spi_host_device_t (e.g. SPI2_HOST, SPI3_HOST).
+  pin-sclk:
+    type: phandle-array
+    default: GPIO_PIN_SPEC_NONE
+  pin-mosi:
+    type: phandle-array
+    default: GPIO_PIN_SPEC_NONE
+    description: MOSI (Data 0) pin
+  pin-miso:
+    type: phandle-array
+    default: GPIO_PIN_SPEC_NONE
+    description: MISO (Data 1) pin
+  pin-wp:
+    type: phandle-array
+    default: GPIO_PIN_SPEC_NONE
+    description: WP (Data 2) pin
+  pin-hd:
+    type: phandle-array
+    default: GPIO_PIN_SPEC_NONE
+    description: HD (Data 3) pin
+  max-transfer-size:
+    type: int
+    default: 0
+    description: |
+      Data transfer size limit in bytes. 
+      0 means the platform decides the limit.