Move remaining code to app module

There's still some stuff that could potentially go elsewhere but I think it's enough for now.

src/app/qml/RemoveChildDialog.qml

@@ -0,0 +1,49 @@
+// SPDX-FileCopyrightText: 2023 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+import QtQuick
+import QtQuick.Layouts
+
+import org.kde.kirigami as Kirigami
+import org.kde.kirigamiaddons.formcard as FormCard
+
+import org.kde.neochat
+
+Kirigami.Dialog {
+    id: root
+
+    required property NeoChatRoom parentRoom
+
+    required property string roomId
+
+    required property string displayName
+
+    required property string parentDisplayName
+
+    required property bool canSetParent
+
+    required property bool isDeclaredParent
+
+    title: i18nc("@title", "Remove Child")
+
+    width: Math.min(applicationWindow().width, Kirigami.Units.gridUnit * 24)
+
+    standardButtons: Kirigami.Dialog.Ok | Kirigami.Dialog.Cancel
+
+    onAccepted: parentRoom.removeChild(root.roomId, removeOfficalCheck.checked)
+
+    contentItem: ColumnLayout {
+        spacing: 0
+        FormCard.FormTextDelegate {
+            text: i18n("The child %1 will be removed from the space %2", root.displayName, root.parentDisplayName)
+            textItem.wrapMode: Text.Wrap
+        }
+        FormCard.FormCheckDelegate {
+            id: removeOfficalCheck
+            visible: root.isDeclaredParent
+            enabled: root.canSetParent
+            text: i18n("The current space is the official parent of this room, should this be cleared?")
+            checked: root.canSetParent
+        }
+    }
+}