Feature request / UX - Image manager in Assets

Initially reported on: https://github.com/mautic/mautic/issues/1615


Description
The image manager is not very easy to access. You have to go in the editor of the email builder or the landing page builder to have this ability.

UX Recommandation
Add an access to the image manager in the left-hand menu Assets with 2 sub-menus:

  • Images
  • Docs
    There, you’ll have the ability to upload and manage massively your images without the need to go in any editor.