Describe the properties of most commonly-used QML types

The current approach for the 2D types is to link to the QML or Qt Quick module documentation. Because the property names and their location in the UI don't altogether match those in the modules, this can be confusing and requires an extra effort from the reader.

Therefore, describe using the following often needed types in more detail:

• Shapes
• Text
• Images
• User interaction methods
• Lists and other data models
• Animation types
• Visual Effects

Also move information about "Positioning Items" to a separate topic and describe the properties of the Positioner and Layout types in more detail.

This approach is already used for 3D types: https://doc.qt.io/qtdesignstudio/studio-3d-components.html