Set default dataset results sorting to date descending

src/app/elasticsearch/models/elasticsearch-options.model.ts

@@ -66,7 +66,7 @@ export class ElasticsearchOptions {
 
     // Need to be done in order to avoid object reference copy
     this._sortOptions = {
-      value: 'relevance',
+      value: 'date',
       order: 'desc',
     };
     if (data && data.sortOptions != null) {
@@ -149,7 +149,7 @@ export class ElasticsearchOptions {
 
     // Need to be done in order to avoid object reference copy
     this._sortOptions = {
-      value: 'relevance',
+      value: 'date',
       order: 'desc',
     };
     if (data && data.sortOptions != null) {