Improve documentation

Improve wording consistency, fix types, add more information about default value, ...

Following component were reworked during this batch:

• AbstractItemViewHeader.qml
• Action.qml
• ActionTextField.qml
• ActionToolBar.qml
• ApplicationItem.qml
• ApplicationWindow.qml
• Avatar.qml
• BasicListItem.qml
• Card.qml
• CardsGridView.qml
• CardsLayout.qml