Fiori app *Browse Books*: Add missing column labels (#420)

* Add labels for `rating` and `numberOfReviews`
* Add label for `currency.symbol`
* Add label for `descr`
* Add label for `image`

Co-authored-by: Christian Georgi <chgeo@users.noreply.github.com>

fiori/app/browse/fiori-service.cds

@@ -52,9 +52,6 @@ annotate CatalogService.Books with @(UI : {
         },
         {Value : genre.name},
         {Value : price},
-        {
-            Value : currency.symbol,
-            Label : ' '
-        },
+        {Value : currency.symbol},
     ]
 }, );