docs: Added Next.js installation guide & express setup for React (#1984)

* Added Next.js installation guide & express setup for React

* Update react.md

Co-authored-by: Hans Pagel <hanspagel@users.noreply.github.com>

docs/installation/nextjs.md

@@ -0,0 +1,75 @@
+---
+title: Next.js WYSIWYG
+tableOfContents: true
+---
+
+# Next.js
+
+## Introduction
+The following guide describes how to integrate tiptap with your [Next.js](https://nextjs.org/) project.
+
+## Requirements
+* [Node](https://nodejs.org/en/download/) installed on your machine
+* Experience with [React](https://reactjs.org/)
+
+## 1. Create a project (optional)
+If you already have an existing Next.js project, that’s fine too. Just skip this step and proceed with the next step.
+
+For the sake of this guide, let’s start with a new Next.js project called `tiptap-example`. The following command sets up everything we need to get started.
+```bash
+# create a project
+npx create-next-app tiptap-example
+
+# change directory
+cd tiptap-example
+```
+
+## 2. Install the dependencies
+Now that we have a standard boilerplate set up we can get started on getting tiptap up and running! For this we will need to install two packages: `@tiptap/react` and `@tipta/starter-kit` which includes all the extensions you need to get started quickly.
+
+```bash
+# install with npm
+npm install @tiptap/react @tiptap/starter-kit
+
+# install with Yarn
+yarn add @tiptap/react @tiptap/starter-kit
+```
+
+If you followed step 1 and 2, you can now start your project with `npm run dev` or `yarn dev`, and open [http://localhost:3000/](http://localhost:3000/) in your favorite browser. This might be different, if you’re working with an existing project.
+
+## 3. Create a new component
+To actually start using tiptap, you’ll need to add a new component to your app. To do this, first create a directory called `components/`. Now it's time to create our component which we'll call `Tiptap`. To do this put the following example code in `components/Tiptap.js`.
+
+```jsx
+import { useEditor, EditorContent } from '@tiptap/react'
+import StarterKit from '@tiptap/starter-kit'
+
+const Tiptap = () => {
+  const editor = useEditor({
+    extensions: [
+      StarterKit,
+    ],
+    content: '<p>Hello World! 🌎️</p>',
+  })
+
+  return (
+    <EditorContent editor={editor} />
+  )
+}
+
+export default Tiptap;
+```
+
+## 4. Add it to your app
+Now, let’s replace the content of `pages/index.js` with the following example code to use our new `Tiptap` component in our app.
+
+```jsx
+import Tiptap from '../components/Tiptap'
+
+export default function Home() {
+    return (
+         <Tiptap />
+    )
+}
+```
+You should now see tiptap in your browser. Time to give yourself a pat on the back! :)