Split message content into its own module

This is laying some groundwork for the rich text chatbar.

src/messagecontent/LoadComponent.qml

@@ -0,0 +1,33 @@
+// SPDX-FileCopyrightText: 2024 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-or-later OR LicenseRef-KDE-Accepted-GPL
+
+import QtQuick
+import QtQuick.Controls as QQC2
+import QtQuick.Layouts
+
+import org.kde.kirigami as Kirigami
+
+import org.kde.neochat
+
+/**
+ * @brief A component to show that part of a message is loading.
+ */
+RowLayout {
+    id: root
+
+    required property string display
+
+    Layout.fillWidth: true
+    Layout.maximumWidth: Message.maxContentWidth
+    spacing: Kirigami.Units.smallSpacing
+
+    QQC2.BusyIndicator {}
+    Kirigami.Heading {
+        id: loadingText
+        Layout.fillWidth: true
+        verticalAlignment: Text.AlignVCenter
+        level: 2
+        text: root.display.length > 0 ? root.display : i18n("Loading")
+    }
+}
+