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/_i18n/i18n.properties

@@ -6,6 +6,8 @@ Author = Author
 AuthorID = Author ID
 Stock = Stock
 Name = Name
+Description = Description
+Image = Image
 AuthorName = Author's Name
 DateOfBirth = Date of Birth
 DateOfDeath = Date of Death
@@ -17,6 +19,9 @@ Authors = Authors
 Order = Order
 Orders = Orders
 Price = Price
+Currency = Currency
+Rating = Rating
+NumberOfReviews = Number of Reviews
 
 Genre = Genre
 Genres = Genres