Improve PlaybackManager stability, added PlaybackBar

- PlaybackManager now takes ownership of set items
- PlaybackManager can play items just by their itemId, avoids useless
  item creation on the QML side of things.
- Allow calling Jellyfin::registerTypes with a different URI
- Minor code cleanup

sailfish/qml/components/PlaybackBar.qml

@@ -0,0 +1,106 @@
+/*
+Sailfin: a Jellyfin client written using Qt
+Copyright (C) 2021 Chris Josten
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2.1 of the License, or (at your option) any later version.
+
+This library is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+import QtQuick 2.6
+import QtQuick.Layouts 1.1
+import QtMultimedia 5.6
+import Sailfish.Silica 1.0
+
+import nl.netsoj.chris.Jellyfin 1.0
+
+import "../"
+
+/**
+ *
+ * +---+--------------------------------------+
+ * |\   /|                              +---+ |
+ * | \ / |   Media title                |   | |
+ * |  X  |                              | ⏸︎| |
+ * | / \ |   Artist 1, artist 2         |   | |
+ * |/   \|                              +---+ |
+ * +-----+------------------------------------+
+ */
+DockedPanel {
+    height: content.height
+    width: parent.width
+    property PlaybackManager manager
+
+    RowLayout {
+        id: content
+        width: parent.width
+        height: Theme.itemSizeLarge
+        RemoteImage {
+            Layout.fillHeight: true
+            Layout.preferredWidth: content.height
+            blurhash: manager.item.imageBlurHashes["Primary"][manager.item.imageTags["Primary"]]
+            source: Utils.itemImageUrl(ApiClient.baseUrl, manager.item, "Primary", {"maxWidth": parent.width})
+            fillMode: Image.PreserveAspectCrop
+        }
+        Item { height: 1; Layout.preferredWidth: Theme.paddingMedium; } // Padding
+        Column {
+            Layout.fillWidth: true
+            Layout.alignment: Qt.AlignVCenter | Qt.AlignLeft
+            Layout.minimumWidth: 10 * Theme.pixelRatio
+            Label {
+                text: manager.item == null ? qsTr("No media selected") : manager.item.name
+                width: parent.width
+                font.pixelSize: Theme.fontSizeMedium
+                truncationMode: TruncationMode.Fade
+            }
+            Label {
+                text: {
+                    if (manager.item == null) return qsTr("Play some media!")
+                    console.log(manager.item.type)
+                    switch(manager.item.type) {
+                    case "Audio":
+                        return manager.item.artists.join(", ")
+                    }
+                }
+                width: parent.width
+                font.pixelSize: Theme.fontSizeSmall
+                truncationMode: TruncationMode.Fade
+                color: highlighted ? Theme.secondaryHighlightColor : Theme.secondaryColor
+            }
+        }
+
+        Item { height: 1; Layout.preferredWidth: Theme.paddingMedium; } // Padding
+        IconButton {
+            id: playButton
+            Layout.preferredHeight: Theme.iconSizeMedium
+            Layout.preferredWidth: Theme.iconSizeMedium
+            icon.source: appWindow.mediaPlayer.playbackState === MediaPlayer.PlayingState
+                         ? "image://theme/icon-m-pause" : "image://theme/icon-m-play"
+            onClicked: appWindow.mediaPlayer.playbackState === MediaPlayer.PlayingState
+                ? appWindow.mediaPlayer.pause()
+                : appWindow.mediaPlayer.play()
+        }
+        Item { height: 1; Layout.preferredWidth: Theme.paddingMedium; } // Padding
+    }
+
+    ProgressBar {
+        anchors.verticalCenter: parent.top
+        width: parent.width
+        leftMargin: Theme.itemSizeLarge
+        rightMargin: 0
+        minimumValue: 0
+        value: appWindow.mediaPlayer.position
+        maximumValue: appWindow.mediaPlayer.duration
+        indeterminate: [MediaPlayer.Loading, MediaPlayer.Buffering].indexOf(appWindow.mediaPlayer.status) >= 0
+    }
+}