Improve audio focus management (#4707)

* Extract Audio focus management to its own modules.

* Request Audio focus when playing a voice message.

* Add missing dependency.
(and remove a duplicated one)

* Request Audio focus when playing a video/audio in the media viewer.

* Pause audio when audio focus is lost.

* Rename class

* Fix tests

* Fix detekt issue.

* Audio focus: let the system handle automatic ducking when playing media.

* Document and update API

* Remove useless space.

libraries/audio/impl/build.gradle.kts

@@ -0,0 +1,25 @@
+import extension.setupAnvil
+
+/*
+ * Copyright 2025 New Vector Ltd.
+ *
+ * SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Element-Commercial
+ * Please see LICENSE files in the repository root for full details.
+ */
+plugins {
+    id("io.element.android-library")
+}
+
+android {
+    namespace = "io.element.android.libraries.audio.impl"
+}
+
+setupAnvil()
+
+dependencies {
+    api(projects.libraries.audio.api)
+
+    implementation(libs.androidx.corektx)
+    implementation(libs.dagger)
+    implementation(projects.libraries.di)
+}