UI design improvements and hierarchy panel updates

This update focuses on UI design improvements and introduces a new hierarchy panel for better object management.

Changes

• UI design improvements. Fixed errors on the light theme.
• Top-left bar now includes a search input to quickly filter the objects in the hierarchy.
• There is a new hierarchy panel (a complete code rewrite!).
• The hierarchy panel now allows the selection of objects the same way as in the 3D viewport.
• Object grouping was improved and now works as expected.
• Selection on 3D viewport was improved and it is now consistent with the hierarchy panel.
• Selection box fixes and improvements.
• Circle object is now Ellipse, and it allows proper pie and ring shapes, as well as side segments.
• Star object also considers angles for pie.
• Cylinder now has a toggle for caps.
• Minor improvements in shape features.
• Fixes on the importer of external files.
• Fix issue of video not stopping after deletion.
• Fix issue when importing images from the library.
• A bunch of minor improvements and bug fixes.