refactor(framework): remove render method (#8501)

Removed the deprecated `UI5Element#render` method of the UI5Element class and replaced it with `UI5Element#renderer`.

BREAKING CHANGE:  Removed `UI5Element#render` method in favour of `UI5Element#renderer`. If you previously used "render"
```js
class MyClass extends UI5Element {
    static get render() {
        return litRenderer;
    }
}
```
start using "renderer"
```ts
class MyClass extends UI5Element {
    static get renderer() {
        return litRenderer;
    }
}
```

Related to [#8461](#8461)

Author: nnaydenow

packages/base/test/elements/WithStaticArea.js

@@ -0,0 +1,77 @@
+import UI5Element from "../../dist/UI5Element.js";
+import litRender, { html } from "../../dist/renderer/LitRenderer.js";
+
+const metadata = {
+	tag: "ui5-with-static-area",
+	properties: {
+		/**
+		 * Defines whether the static area item will be rendered
+		 */
+		staticContent: {
+			type: Boolean,
+		}
+	},
+	slots: {
+
+	}
+};
+
+class WithStaticArea extends UI5Element {
+	static get metadata() {
+		return metadata;
+	}
+
+	static get renderer() {
+		return litRender;
+	}
+
+	static get template() {
+		return element => {
+			// access effectiveDir getter to mark control as RTL-aware (test changes dir attribute and expects rerender)
+			return html`
+				<div dir=${element.effectiveDir}>
+					WithStaticArea works!
+				</div>`;
+		};
+	}
+
+	static get staticAreaTemplate() {
+		return element => {
+			return html`
+				<div class="ui5-with-static-area-content">
+					Static area content.
+				</div>`;
+		};
+	}
+
+	static get styles() {
+		return `
+			:host {
+				display: inline-block;
+				border: 1px solid black;
+				color: red;
+			}`;
+	}
+
+	async addStaticArea() {
+		if (!this.staticContent) {
+			return;
+		}
+
+		// Require static area item
+		const staticArea = await this.getStaticAreaItemDomRef();
+		this.responsivePopover = staticArea.querySelector(".ui5-with-static-area-content");
+		return this.responsivePopover;
+	}
+
+	onBeforeRendering() {
+		this.addStaticArea();
+	}
+	onAfterRendering() {}
+	onEnterDOM() {}
+	onExitDOM() {}
+}
+
+WithStaticArea.define();
+
+export default WithStaticArea;