feat(cli): add last focused workspace cmd

This commit adds a new komorebic command, focus-last-workspace, which
switches to the last focused workspace on the focused monitor (if there
is one).

komorebi-core/src/lib.rs

@@ -99,6 +99,7 @@ pub enum SocketMessage {
     CycleFocusMonitor(CycleDirection),
     CycleFocusWorkspace(CycleDirection),
     FocusMonitorNumber(usize),
+    FocusLastWorkspace,
     FocusWorkspaceNumber(usize),
     FocusWorkspaceNumbers(usize),
     FocusMonitorWorkspaceNumber(usize, usize),