Refactor the purchase-order table

- Filter by order status

InvenTree/templates/status_codes.html

@@ -1,3 +1,6 @@
+/*
+ * Status codes for the {{ label }} model.
+ */
 var {{ label }}Codes = {
     {% for opt in options %}'{{ opt.key }}': {
         key: '{{ opt.key }}',
@@ -6,6 +9,11 @@ var {{ label }}Codes = {
     },{% endfor %}
 };
 
+/* 
+ * Render the status for a {{ label }} object.
+ * Uses the values specified in "status_codes.py"
+ * This function is generated by the "status_codes.html" template
+ */
 function {{ label }}StatusDisplay(key) {
 
     key = String(key);