Add go to depot and sell vehicle orders

Controlled by a setting (default off)

src/table/settings.ini

@@ -4177,6 +4177,14 @@ str      = STR_CONFIG_SETTING_ADV_SIG_BRIDGE_TUN_MODES
 strhelp  = STR_CONFIG_SETTING_ADV_SIG_BRIDGE_TUN_MODES_HELPTEXT
 cat      = SC_EXPERT
 
+[SDTC_BOOL]
+var      = gui.show_depot_sell_gui
+flags    = SLF_NOT_IN_SAVE | SLF_NO_NETWORK_SYNC
+def      = false
+str      = STR_CONFIG_SETTING_SHOW_DEPOT_SELL_GUI
+strhelp  = STR_CONFIG_SETTING_SHOW_DEPOT_SELL_GUI_HELPTEXT
+cat      = SC_EXPERT
+
 ; For the dedicated build we'll enable dates in logs by default.
 [SDTC_BOOL]
 ifdef    = DEDICATED