Move src/voice to src/audio for better naming

Many of these files are used by Audio and Voice messages.

Fixes https://github.com/vector-im/element-web/issues/18131

src/audio/ManagedPlayback.ts

@@ -0,0 +1,37 @@
+/*
+Copyright 2021 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { DEFAULT_WAVEFORM, Playback } from "./Playback";
+import { PlaybackManager } from "./PlaybackManager";
+
+/**
+ * A managed playback is a Playback instance that is guided by a PlaybackManager.
+ */
+export class ManagedPlayback extends Playback {
+    public constructor(private manager: PlaybackManager, buf: ArrayBuffer, seedWaveform = DEFAULT_WAVEFORM) {
+        super(buf, seedWaveform);
+    }
+
+    public async play(): Promise<void> {
+        this.manager.playOnly(this);
+        return super.play();
+    }
+
+    public destroy() {
+        this.manager.destroyPlaybackInstance(this);
+        super.destroy();
+    }
+}