BUGFIX: add empty query parts for should and must_not in default bool query

This allows to use the existing API "appendAtPath" as well with the paths:
"query.filtered.query.bool.should" and "query.filtered.query.bool.must_not"
which is helpful from time to time.

Other than that, this change has no side-effects.

Author: skurfuerst

Classes/Flowpack/ElasticSearch/ContentRepositoryAdaptor/Eel/ElasticSearchQueryBuilder.php

@@ -101,7 +101,9 @@ class ElasticSearchQueryBuilder implements QueryBuilderInterface, ProtectedConte
                             [
                                 'match_all' => []
                             ]
-                        ]
+                        ],
+                        'should' => [],
+                        'must_not' => []
                     ]
 
                 ],

Tests/Unit/Eel/ElasticSearchQueryBuilderTest.php

@@ -55,7 +55,9 @@ public function basicRequestStructureTakesContextNodeIntoAccount()
                         'bool' => [
                             'must' => [
                                 ['match_all' => []]
-                            ]
+                            ],
+                            'should' => [],
+                            'must_not' => []
                         ]
                     ],
                     'filter' => [