Mobile Responsiveness and Layout Enhancements for Admin Ui

[VargaJoe]

• The admin interface does not resize appropriately, resulting in the right-side content/editorial area does not fit, is not visible or is cut off.
• The folder tree should be collapsible to optimize screen real estate and the right-side content area should not be visible when the folder tree is opened.
• The folder tree may be deemed unnecessary if parent navigation is introduced to the content area.
• The "New Content" and "Upload" buttons (depicted by the "+" icon) are not visible.
• This visibility issue could be resolved by incorporating the "New Item" shortcut and the "Upload" action within the content actions (...) menu.
• Although the leftmost navigation is well-designed, there is a lack of proper ordering