remove unused use statements

core/Application/Kernel/EnvironmentValidator.php

core/Date.php

core/Metrics/Formatter.php

core/Period/Day.php

core/Period/Range.php

core/Period/Week.php

core/Plugin/ControllerAdmin.php

core/Plugin/Manager.php

core/Tracker.php

core/Tracker/ScheduledTasksRunner.php

plugins/API/Controller.php

plugins/API/RowEvolution.php

plugins/API/tests/Integration/RssRendererTest.php

plugins/Actions/Actions.php

plugins/Actions/Metrics.php

plugins/Actions/Reports/GetEntryPageUrls.php

plugins/Actions/Reports/GetExitPageUrls.php

plugins/Actions/Reports/GetPageTitles.php

plugins/Annotations/Controller.php

plugins/BulkTracking/Tracker/Handler.php