Do not use item_assets to obtain asset data

As we need to check the protocol for href, we cannot rely on this extension anymore.

adapters/klab.ogc/src/main/java/org/integratedmodelling/klab/stac/STACCollectionParser.java

@@ -25,10 +25,6 @@ public static String readCollectionId(JSONObject collection) {
         return collection.getString("id");
     }
 
-    private static JSONObject readItemAssets(JSONObject collection) {
-        return collection.getJSONObject("item_assets");
-    }
-
     /**
      * Obtains the geometry from the collection data.
      * Currently, only available for dynamic collections.
@@ -82,14 +78,6 @@ public static JSONObject readAssetsFromCollection(String collectionUrl, JSONObje
             return collection.getJSONObject("assets");
         }
 
-        // item_assets is a shortcut for obtaining information about the assets
-        // https://github.com/stac-extensions/item-assets
-        if (collection.has("item_assets")) {
-            if (!collection.getJSONObject("item_assets").isEmpty()) {
-                return STACCollectionParser.readItemAssets(collection);
-            }
-        }
-
         // TODO Move the query to another place. 
         String parameters = "?collections=" + collectonId + "&limit=1";
         HttpResponse<JsonNode> response = Unirest.get(searchEndpoint.get() + parameters).asJson();