implemented adding stock items to documents

Signed-off-by: Stephan Richter <s.richter@srsoftware.de>

frontend/src/routes/document/PositionSelector.svelte

@@ -29,14 +29,24 @@
     }
 
     function itemSelected(item){
+        let unit_price = null;
+        let description = '';
+        for (let prop of item.properties) {
+            if (prop.name.toLowerCase().indexOf(t('price').toLowerCase())>-1){
+                unit_price = 100*prop.value.replace(',','.');
+            } else {
+                description += `* ${prop.name}: ${prop.value}\n`;
+            }
+        }
+
         select({
             item_code   : item.code,
             title       : item.name,
-            description : item.description.source,
+            description : description,
             amount      : 1,
-            unit        : item.unit,
-            unit_price  : item.unit_price,
-            tax         : item.tax
+            unit        : t('pieces'),
+            unit_price  : unit_price,
+            tax         : 0
         });
     }