Add configuration option to turn off workspace bar

src/cfgparse.l

@@ -93,6 +93,7 @@ ipc_socket                      { BEGIN(BIND_AWS_COND); return TOKIPCSOCKET; }
 new_container                   { return TOKNEWCONTAINER; }
 new_window                      { return TOKNEWWINDOW; }
 focus_follows_mouse             { return TOKFOCUSFOLLOWSMOUSE; }
+workspace_bar                   { return TOKWORKSPACEBAR; }
 default                         { yylval.number = MODE_DEFAULT; return TOKCONTAINERMODE; }
 stacking                        { yylval.number = MODE_STACK; return TOKCONTAINERMODE; }
 tabbed                          { yylval.number = MODE_TABBED; return TOKCONTAINERMODE; }