Add strip_workspace_name

See the issue #3163 (https://github.com/i3/i3/issues/3163).

Add strip_workspace_name to strip off the workspace name.

i3bar/include/configuration.h

@@ -52,6 +52,7 @@ typedef struct config_t {
     bool disable_binding_mode_indicator;
     bool disable_ws;
     bool strip_ws_numbers;
+    bool strip_ws_name;
     char *bar_id;
     char *command;
     char *fontname;