Port implicit default content items to use contentItem: property

Port implicit default content items to use contentItem: property

See also frameworks/kirigami!1338 (merged) and frameworks/kirigami!1340 (closed)

Port NavigationTabBar from removed shadow property

Fix anchors bindings

Null is not a valid value to assign. Anchors should be explicitly reset with undefined value instead.

Add missing newline after printing an error message

Remove ToolTip attached objects from Actions

This is not supported and won't work this way. SwipeListItem would display tooltips for its action buttons anyway. If a custom text is desired, Kirigami.Action type provides a special tooltip property.

Move PlaylistImporter component declaration out of Action

Action has no default property for child objects. This component never worked, it just failed to load.

Fix Units property name

Explicitly specify arguments in signal handlers

Injection of parameters into signal handlers is deprecated. Use JavaScript functions with formal parameters instead.

PlaylistPage: Refactor data flow to fix "missing" required property

QML engine is not happy with aliases on a required property. It needs some direct binding at declaration site.