Instead of having a bunch of handlers in various places messing with various settings,
try to use declarative bindings where possible.

* Remove separate passive timer, instead re-use the pendingDelegateRemoval property
  which has its own timer. This way, when a device is unmounted, device notifier stays
  active until the notification has cleared, however, when the device is yanked out manually,
  it disappears right away
* Don't break binding on Plasmoid.active to ensure its state is always proper depending on
  whether a device or not is present (the linked bug)
* Create tooltip declaratively rather than imperatively

BUG: 362992
FIXED-IN: 5.7.0

Differential Revision: https://phabricator.kde.org/D1793