docs: New fiddle example 'Create a new window' (#20480)

* add: New fiddle for Manage Windows section example

* Delete package.json

Not needed

* Address issue with .gitignore file, load new window, removing unwanted css class

* Delete package.json

* Pushing change regarding the use of shell.OpenExternal API with an event listener for the href tag on the link

docs/fiddles/windows/manage-windows/new-window/renderer.js

@@ -0,0 +1,19 @@
+const { BrowserWindow } = require('electron').remote
+const { shell } = require('electron').remote
+
+const newWindowBtn = document.getElementById('new-window')
+const link = document.getElementById('browser-window-link')
+
+newWindowBtn.addEventListener('click', (event) => {
+
+  let win = new BrowserWindow({ width: 400, height: 320 })
+
+  win.on('close', () => { win = null })
+  win.loadURL('https://electronjs.org')
+  win.show()
+})
+
+link.addEventListener('click', (e) => {
+  e.preventDefault()
+  shell.openExternal("http://electron.atom.io/docs/api/browser-window")
+})