Refactoring: move all code files into a src directory

src/UI/Base/Lazy.ts

@@ -0,0 +1,15 @@
+import BaseUIElement from "../BaseUIElement"
+
+export default class Lazy extends BaseUIElement {
+    private readonly _f: () => BaseUIElement
+
+    constructor(f: () => BaseUIElement) {
+        super()
+        this._f = f
+    }
+
+    protected InnerConstructElement(): HTMLElement {
+        // The caching of the BaseUIElement will guarantee that _f will only be called once
+        return this._f().ConstructElement()
+    }
+}