Split message content into its own module

This is laying some groundwork for the rich text chatbar.

src/messagecontent/PdfPreviewComponent.qml

@@ -0,0 +1,39 @@
+// SPDX-FileCopyrightText: 2024 Tobias Fella <tobias.fella@kde.org>
+// SPDX-FileCopyrightText: 2024 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.neochat
+
+Rectangle {
+    id: root
+
+    /**
+     * @brief FileTransferInfo for any downloading files.
+     */
+    required property var fileTransferInfo
+
+    /**
+     * @brief The attributes of the component.
+     */
+    required property var componentAttributes
+
+    Layout.preferredWidth: mediaSizeHelper.currentSize.width
+    Layout.preferredHeight: mediaSizeHelper.currentSize.height
+
+    color: "white"
+
+    Image {
+        anchors.fill: root
+        source: root?.fileTransferInfo.localPath ?? ""
+
+        MediaSizeHelper {
+            id: mediaSizeHelper
+            contentMaxWidth: root.Message.maxContentWidth
+            mediaWidth: root.componentAttributes.size.width
+            mediaHeight: root.componentAttributes.size.height
+        }
+    }
+}