Merge bitcoin-core/gui-qml#269: Introduce the Shutdown page

002af83 qml: introduce the Shutdown page (johnny9)
b60c18f qml: introduce the shutdown icon (johnny9)

Pull request description:

  This page appears when quitting by sending an interrupt signal to the node.  The page will clear out the current views while the node is shutting down. This fixes various null errors in the gui when the node is shutdown in the background.

  Based on:
  https://www.figma.com/file/ek8w3n3upbluw5UL2lGhRx/Bitcoin-Core-App-Design?node-id=2643%3A66321&t=3tsT34chWmtE21N9-0

  [![Windows](https://img.shields.io/badge/OS-Windows-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/win64/insecure_win_gui.zip?branch=pull/269)
  [![Intel macOS](https://img.shields.io/badge/OS-Intel%20macOS-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/macos/insecure_mac_gui.zip?branch=pull/269)
  [![Apple Silicon macOS](https://img.shields.io/badge/OS-Apple%20Silicon%20macOS-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/macos_arm64/insecure_mac_arm64_gui.zip?branch=pull/269)
  [![ARM64 Android](https://img.shields.io/badge/OS-Android-green)](https://api.cirrus-ci.com/v1/artifact/github/bitcoin-core/gui-qml/android/insecure_android_apk.zip?branch=pull/269)

ACKs for top commit:
  jarolrod:
    ACK 002af83

Tree-SHA512: 4e86cd26ae8cea9e14c2e141755a0eecc485b430d922b24ee044faf7530546b2d8535e5744c3a8d1558398968e1bf132376c2114c3b9e89fe0ad4f0aa59075a1

Author: hebasto

qml/bitcoin_qml.qrc

@@ -38,6 +38,7 @@
         <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>
@@ -66,6 +67,7 @@
         <file alias="info">res/icons/info.png</file>
         <file alias="network-dark">res/icons/network-dark.png</file>
         <file alias="network-light">res/icons/network-light.png</file>
+        <file alias="shutdown">res/icons/shutdown.png</file>
         <file alias="storage-dark">res/icons/storage-dark.png</file>
         <file alias="storage-light">res/icons/storage-light.png</file>
     </qresource>

qml/imageprovider.cpp

@@ -97,6 +97,11 @@ QPixmap ImageProvider::requestPixmap(const QString& id, QSize* size, const QSize
         return QIcon(":/icons/network-light").pixmap(requested_size);
     }
 
+    if (id == "shutdown") {
+        *size = requested_size;
+        return QIcon(":/icons/shutdown").pixmap(requested_size);
+    }
+
     if (id == "storage-dark") {
         *size = requested_size;
         return QIcon(":/icons/storage-dark").pixmap(requested_size);

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
+        }
+    }
+}