Integrate a markdown editor for create/edit articles

**Description**

In the article create/edit area, the textarea destined to write the article in markdown format should be replaced by a markdown editor.

**Requierements**

- [ ] Integrate markdown edit component in the edit/create article

**Notes**

The library [ngx-markdown-editor](https://www.npmjs.com/package/ngx-markdown-editor) can be used