Add ability to filter parts by "purchasable" status

InvenTree/templates/table_filters.html

@@ -97,6 +97,10 @@ function getAvailableTableFilters(tableKey) {
                 type: 'bool',
                 title: '{% trans "Salable" %}',
             },
+            purchaseable: {
+                type: 'bool',
+                title: '{% trans "Purchasable" %}',
+            },
         };
     }