Some 3D components cannot be added by drag and drop to 3D View

While testing https://bugreports.qt.io/browse/QDS-8774 I noticed that some  3D components cannot be added to project by dragging and dropping to 3D View, but only by dragging to Navigator.  

Created a list of those components, but we need UX to decide whether it would make sense to allow adding those by drag and drop to 3D view.

QtQuick3D module:

• Effect
•  File Instanching
• Instance List
• Instance List Entry
• Skeleton
• Joint
• Morph Target
• Component3D
• Buffer
• Buffer Input
• Pass
• Set Uniform Value
• Shader
• Texture Input

QtQuick3D Effects:

• all

QtQuick3D Helpers:

• Debug View
• Instance model
• Wasd Controller