Add basic example NL entity localizations.

Make secret stash use fluent in one spot as example.

Content.Server/GameObjects/Components/Items/Storage/SecretStashComponent.cs

@@ -66,7 +66,7 @@ namespace Content.Server.GameObjects.Components.Items.Storage
             if (!hands.Drop(itemToHide, _itemContainer))
                 return false;
 
-            Owner.PopupMessage(user, Loc.GetString("You hide {0:theName} in {1}.", itemToHide, SecretPartName));
+            Owner.PopupMessage(user, Loc.GetString("comp-secret-stash-action-hide", ("item", itemToHide), ("this", SecretPartName)));
             return true;
         }