Fix app initialization order

Summary:
Patch inlines the code of the constructor and destructor of the old
QApplication subclass PolicyKitKDE and then reorders things as needed:
* KDBusService for singleton run should be started before any further init
* KLocalizedString::setApplicationDomain & i18n calls should be only done
  after the QApp instance has been created
* KAboutData::setApplicationData best done before doing any D-Bus activity
  as that relies on app metadata
* QCoreApplication::setOrganizationDomain duplicates app metadata
  setting from KAboutData::setApplicationData, only needed before due to
  latter done after first D-Bus activity
* m_listener->deleteLater() in app destructor does not make sense, as
  the listener object is deleted due to being QObject child of the
  QApplication instance

Reviewers: davidedmundson

Reviewed By: davidedmundson

Subscribers: plasma-devel

Tags: #plasma

Differential Revision: https://phabricator.kde.org/D11106