Trackball rewrite (#600)

- Implement generic trackball settings
- Refactor T-Deck trackball driver into generic driver at `Drivers/gpio-trackball-module`
- Automatically bind/unbind trackball devices with LVGL
- Automatically load settings for trackball devices on boot

Modules/lvgl-module/include/lvgl/devices/device_context.h

@@ -0,0 +1,26 @@
+#pragma once
+
+#include <new>
+
+struct Device;
+
+/**
+ * Common driver-data wrapper attached to every LVGL display/indev created by this module: bundles
+ * the kernel Device* with an optional device-type-specific context blob (LvglDisplayCtx,
+ * LvglPointerCtx, LvglTrackballCtx, ...), so each device type doesn't have to store its own Device*
+ * redundantly. Owns context: any resources referenced through it (buffers, cursor objects, etc.)
+ * must be released by the caller before the wrapper is deleted, since context is trivially
+ * destructible and only its own memory is freed here.
+ */
+struct LvglDeviceContext {
+    struct Device* device = nullptr;
+    void* context;
+
+    explicit LvglDeviceContext(void* context) : context(context) {}
+
+    ~LvglDeviceContext() {
+        if (context != nullptr) {
+            ::operator delete(context);
+        }
+    }
+};