feat(wm): add focus-workspaces cmd

This commit adds a new command, focus-workspaces, to allow the user to
change workspaces across all monitors at the same time. I'm not
convinced of the stability of this command and I would strongly
discourage using komorebi in this manner.

resolve #426

komorebi-core/src/lib.rs

@@ -95,6 +95,7 @@ pub enum SocketMessage {
     CycleFocusWorkspace(CycleDirection),
     FocusMonitorNumber(usize),
     FocusWorkspaceNumber(usize),
+    FocusWorkspaceNumbers(usize),
     FocusMonitorWorkspaceNumber(usize, usize),
     FocusNamedWorkspace(String),
     ContainerPadding(usize, usize, i32),