Better image support in used CKEditor widgets

[sveetch]

Is your feature request related to a problem? Please describe.
Currently as from Lotus v0.7.0, image embed in CKEditor is enable through the "image" plugin and some setting to enable the ckeditor uploader. It works but it is not the most user friendly feature.

Especially the file browsing is very basic, there is no way to clean upload images from FS and there is no way to have thumbnailed image in content render (only in file uploader browser listing).

Describe the solution you'd like
First use the image2 plugin instead of the original one, it is a little bit more usable.

Then we need to study a solution for a better file uploader browser. 'ckeditor uploader' have a setting to use a "image processing backend" but it may only be used from browser listing and not content render, it needs to be studied.

Also there is a package https://github.com/nephila/django-ckeditor-filebrowser-filer that seems to enable django-filer usage, which should be an improvement but we will have to manage it as a configuration option, not every one would like or to be able to include it in a project.

Finally, the ckeditor upload views could be overridden to make our own uploader browser.

Additional context
CKEditor 5 has improvement with uploader and there is a django package for it but it would conflict in all project which use DjangoCMS which is highly tied to ckeditor 4

[sveetch]

This is on hold because we are trying to implement a new solution (in #80 ) that would allow to select another editor than just CKEditor 4 from django-ckeditor which is deprecated anyway.

However the image management inside editor is something hard to have in our days , each editor do it in its own way and rarely easy to enable.