Admin view for Category tree is broken with django-admin-styles

[sveetch]

Describe the bug

The admin view for the Category tree is broken because of django-admin-styles that is overrding many custom styles specific to this view.

Environment
Describe your environment:

• Plateform: Window/IOS/Linux distribution
• Python version: Any
• Django version: Any
• Lotus version: 0.9.0

To Reproduce

1. Install Lotus in a project with django-admin-styles
2. Go to the Category tree view in admin
3. Just look at this disaster

Expected behavior
The tree should look at a tree, at least in the same way than without django-admin-styles.

At least we should provide an alternative admin CSS to adapt in the admin styles context.

Additional context
The tree view is currently experimental and planned to be improved.

[sveetch]

Notice we got an alternative CSS for this, it would need to be in documentation or maybe in future coming djangocms-lotus package.

[sveetch]

Patched stylesheet for category tree admin with admin-style has been included in https://github.com/emencia/djangocms-lotus