Search / Similar document improvement.

When using more like this query in Elastic
(https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-mlt-query.html)
it can be sometimes useful to be able to compare the full document for
better match.

Configuration like:
```json
{
    "like": [
        {
            "_id": null
        }
    ],
    "analyzer": "english",
    "minimum_should_match": "40%"
}
```
will search for
```json
{
    "like": [
        {
            "_id": "f48b5a47-1394-4667-81fd-b2e515593d20"
        },
        "Copernicus EEA38 Boundary Layer with 250 m buffer (raster 20m), version 1, Nov. 2022"
    ],
    "analyzer": "english",
    "minimum_should_match": "40%"
}
```

Add documentation about the configuration of more like this query.

web-ui/src/main/resources/catalog/components/search/mdview/mdviewDirective.js

@@ -161,7 +161,22 @@
               scope.size
             );
 
-            query.query.bool.must[0].more_like_this.like = scope.md.resourceTitle;
+            function setMoreLikeThisFields(fields) {
+              var config = query.query.bool.must[0].more_like_this.like;
+              if (Array.isArray(config)) {
+                config.forEach(function(field) {
+                  if (typeof field === 'object' && field._id !== undefined) {
+                    field._id = scope.md.uuid;
+                  }
+                });
+                config.push(scope.md.resourceTitle);
+              } else {
+                config = scope.md.resourceTitle;
+              }
+              query.query.bool.must[0].more_like_this.like = config;
+            }
+
+            setMoreLikeThisFields();
 
             var resourceType = scope.md.resourceType
               ? scope.md.resourceType[0]

web-ui/src/main/resources/catalog/js/CatController.js

@@ -314,17 +314,11 @@
             moreLikeThisSameType: true,
             moreLikeThisConfig: {
               more_like_this: {
-                fields: [
-                  "resourceTitleObject.langeng"
-                  // "resourceAbstractObject.default",
-                  // "tag.raw"
-                ],
-                like: null,
-                min_term_freq: 1,
-                min_word_length: 3,
-                max_query_terms: 35,
+                like: [{
+                 "_id": null
+                }],
                 analyzer: "english",
-                minimum_should_match: "70%"
+                minimum_should_match: "40%"
               }
             },
             facetTabField: "",