qml: introduce the Shutdown page

Author: johnny9

qml/bitcoin_qml.qrc

@@ -35,6 +35,7 @@
         <file>pages/node/NodeRunner.qml</file>
         <file>pages/node/NodeSettings.qml</file>
         <file>pages/node/Peers.qml</file>
+        <file>pages/node/Shutdown.qml</file>
         <file>pages/onboarding/OnboardingBlockclock.qml</file>
         <file>pages/onboarding/OnboardingConnection.qml</file>
         <file>pages/onboarding/OnboardingCover.qml</file>

qml/pages/main.qml

@@ -25,6 +25,14 @@ ApplicationWindow {
         anchors.fill: parent
     }
 
+    Connections {
+        target: nodeModel
+        function onRequestedShutdown() {
+            main.clear()
+            main.push(shutdown)
+        }
+    }
+
     Component {
         id: onboardingWizard
         SwipeView {
@@ -43,6 +51,11 @@ ApplicationWindow {
         }
     }
 
+    Component {
+        id: shutdown
+        Shutdown {}
+    }
+
     Component {
         id: node
         SwipeView {

qml/pages/node/Shutdown.qml

@@ -0,0 +1,37 @@
+// Copyright (c) 2023 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+import QtQuick 2.15
+import QtQuick.Controls 2.15
+import QtQuick.Layouts 1.15
+import "../../controls"
+
+Page {
+    background: null
+
+    ColumnLayout {
+        anchors.centerIn: parent
+        width: parent.width
+        spacing: 10
+        Button {
+            Layout.alignment: Qt.AlignCenter
+            Layout.bottomMargin: 20
+            background: null
+            icon.source: "image://images/shutdown"
+            icon.color: Theme.color.neutral9
+            icon.width: 60
+            icon.height: 60
+        }
+        Header {
+            Layout.alignment: Qt.AlignCenter
+            Layout.fillWidth: true
+            Layout.leftMargin: 20
+            Layout.rightMargin: 20
+            header: qsTr("Saving...")
+            headerBold: true
+            description: qsTr("Do not shut down the computer until this is done.")
+            descriptionColor: Theme.color.neutral7
+        }
+    }
+}