feat(wm): add promote-focus command

This commit adds a promote-focus command to complement the promote
command.

resolve #203

komorebi-core/src/lib.rs

@@ -52,6 +52,7 @@ pub enum SocketMessage {
     SendContainerToMonitorWorkspaceNumber(usize, usize),
     MoveWorkspaceToMonitorNumber(usize),
     Promote,
+    PromoteFocus,
     ToggleFloat,
     ToggleMonocle,
     ToggleMaximize,