More demo stubs (#2529)

* More demo stubs

* History stub actually generates mocks

* More tweaks

* Add more entities

demo/src/stubs/template.ts

@@ -0,0 +1,9 @@
+import { MockHomeAssistant } from "../../../src/fake_data/provide_hass";
+
+export const mockTemplate = (hass: MockHomeAssistant) => {
+  hass.mockAPI("template", () =>
+    Promise.reject({
+      body: { message: "Template dev tool does not work in the demo." },
+    })
+  );
+};