auto hide popup when it opened itself
Summary:
when the device notifier pops up automatically, leave it open
if there is no user activity, if there is any, close after around
3 seconds. Suspend the countdown if the notifier window either has
focus or the mouse cursor is over it, leaving the user the time to
go interact. if it doesn't have focus and the mouse leaves, resume
the countdown
replaces D10591
Test Plan:
tested for a while in a real world usage, it behaves in a fairly natural
way
Reviewers: Plasma, broulik
Reviewed By: Plasma, broulik
Subscribers: ngraham, plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D10921