[lockscreen] Extract top panel components from panel containment into its own component, so it can be reused on the lockscreen

Extract the panel containment's top panel into its own component and use it on the lockscreen instead of the current copy-pasted component. The indicator providers will likely need to become singletons. The volume provider will need to be looked at as the osd likely cannot appear on the lockscreen as is without significant changes.

Quicksettings will also need to have the ability to be adjusted for lockscreen behaviour.