docs: expand tutorial (#34604)

* docs: base tutorial update

* more docs

* zzz

* remove unused images

docs/fiddles/tutorial-preload/preload.js

@@ -0,0 +1,7 @@
+const { contextBridge } = require('electron');
+
+contextBridge.exposeInMainWorld('versions', {
+  node: () => process.versions.node,
+  chrome: () => process.versions.chrome,
+  electron: () => process.versions.electron,
+});