Drop the Workspace::slotSwitchWindowFoo methods
Summary:
They were only delegating into switchWindow(Direction), so let's do the
same through std::bind in kwinbindings and delegate to it directly in
scripting's WorkspaceWrapper.
Test Plan: Not yet, want to add test case for Workspace::switchWindow
Subscribers: plasma-devel
Tags: Plasma
Differential Revision: https://phabricator.kde.org/D6791