Better Vue integration

[thezboe]

Is your feature request related to a problem? Please describe.
The Vue integration works, but doesn't take advantage of nor allow us to use Vue's great features. It's difficult to get params into dockview components, and params nor event handlers can't be passed to title bar actions because of how they are programmatically created.

Describe the solution you'd like
Take advantage of Vue's slot system to allow the user to defined the components they want docked inside DockView and actions in the title bar.