New widget button

[vcoisne]

Fix

Describe your request

In the homepage of the admin panel, we show an "add widget" button but when we click on it nothing happens.

It would be great to have some availables to be added or link to the docs about adding new widgets i.e https://www.youtube.com/watch?v=En5zqXHdze8 or https://strapi.io/blog/how-to-build-a-admin-panel-widget-plugin-for-strapi?utm_campaign=DevRel-%20Content&utm_source=custom-widget

Steps to reproduce the behavior

1. Go to admin homepage
2. Click on 'add widget"
3. See error in the popup

[alex-strapi]

Let's come up with some ideas for this, happy to work on it