v0.6.1 - STL format support

This release adds 2 new features:

• support for STL files, import & export
• dropping models files / folders into the app imports them

This release comes with a few fixes in imports, undo/redo history, and how boolean operations are applied.

The next major change I'd like to release is about replacing relative scaling with actual resizing in absolute values. Also adding a few more options for exports, UI cleanup as soon as Godot 4.5 gets released, adding WASD camera moves, and updating mouse manipulation mappings to more common patterns.

Big kudos to hopelessdecoy for reporting issues in our discord channel!