Transcode stream refactor (#609)

* Remove forceMkv and forceHEVC
* Add HLS support and refactor
* Add new streaming endpoints

graphql/documents/queries/scene.graphql

@@ -53,4 +53,12 @@ query ParseSceneFilenames($filter: FindFilterType!, $config: SceneParserInput!)
       tag_ids
     }
   }
-}
+}
+
+query SceneStreams($id: ID!) {
+  sceneStreams(id: $id) {
+    url
+    mime_type
+    label
+  }
+}