add manage track design window (UNTESTED)

src/localisation/string_ids.h

@@ -1295,6 +1295,13 @@ enum {
 	STR_ROLLER_COASTER_DESIGNER = 3344,
 	STR_TRACK_DESIGNS_MANAGER = 3345,
 
+	STR_TRACK_MANAGE_RENAME = 3348,
+	STR_TRACK_MANAGE_DELETE = 3349,
+
+	STR_CANT_RENAME_TRACK_DESIGN = 3352,
+
+	STR_ARE_YOU_SURE_YOU_WANT_TO_PERMANENTLY_DELETE_TRACK = 3357,
+	STR_CANT_DELETE_TRACK_DESIGN = 3358,
 	STR_NO_TRACK_DESIGNS_OF_THIS_TYPE = 3359,
 	STR_WARNING = 3360,
 	STR_TOO_MANY_TRACK_DESIGNS_OF_THIS_TYPE = 3361,