Add more OpenSubsonic fields

- mediaType
- musicBrainzId (Child)

server/subsonic/responses/.snapshots/Responses Shares with data should match .JSON

@@ -14,11 +14,13 @@
             "title": "title",
             "album": "album",
             "artist": "artist",
-            "genres": [],
             "duration": 120,
             "isVideo": false,
+            "mediaType": "",
+            "musicBrainzId": "",
             "bpm": 0,
-            "comment": ""
+            "comment": "",
+            "genres": []
           },
           {
             "id": "2",
@@ -26,11 +28,13 @@
             "title": "title 2",
             "album": "album",
             "artist": "artist",
-            "genres": [],
             "duration": 300,
             "isVideo": false,
+            "mediaType": "",
+            "musicBrainzId": "",
             "bpm": 0,
-            "comment": ""
+            "comment": "",
+            "genres": []
           }
         ],
         "id": "ABC123",