Introduce MediaManager

Currently, this is only to pause playback of other media when something new starts playing.
In the future, it will also be used for other things, like call ringing, etc.

src/qml/AudioComponent.qml

@@ -105,6 +105,7 @@ ColumnLayout {
                 icon.name: "media-playback-start"
                 onClicked: {
                     audio.source = root.fileTransferInfo.localPath;
+                    MediaManager.startPlayback();
                     audio.play();
                 }
             }
@@ -123,6 +124,15 @@ ColumnLayout {
         }
     ]
 
+    Connections {
+        target: MediaManager
+        function onPlaybackStarted() {
+            if (audio.playbackState === MediaPlayer.PlayingState) {
+                audio.pause();
+            }
+        }
+    }
+
     RowLayout {
         QQC2.ToolButton {
             id: playButton

src/qml/VideoComponent.qml

@@ -118,7 +118,10 @@ Video {
             PropertyChanges {
                 target: playButton
                 icon.name: "media-playback-start"
-                onClicked: root.play()
+                onClicked: {
+                    MediaManager.startPlayback();
+                    root.play();
+                }
             }
         },
         State {
@@ -136,6 +139,15 @@ Video {
         }
     ]
 
+    Connections {
+        target: MediaManager
+        function onPlaybackStarted() {
+            if (root.playbackState === MediaPlayer.PlayingState) {
+                root.pause();
+            }
+        }
+    }
+
     Image {
         id: mediaThumbnail
         anchors.fill: parent
@@ -350,6 +362,7 @@ Video {
             if (root.playbackState == MediaPlayer.PlayingState) {
                 root.pause();
             } else {
+                MediaManager.startPlayback();
                 root.play();
             }
         } else {
@@ -375,6 +388,7 @@ Video {
 
     function playSavedFile() {
         root.stop();
+        MediaManager.startPlayback();
         root.play();
     }
 }