Split message content into its own module

This is laying some groundwork for the rich text chatbar.

src/messagecontent/MessageComponentChooser.qml

@@ -0,0 +1,26 @@
+// 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 Qt.labs.qmlmodels
+
+import org.kde.neochat
+
+/**
+ * @brief Select a message component based on a MessageComponentType.
+ */
+BaseMessageComponentChooser {
+    id: root
+
+    DelegateChoice {
+        roleValue: MessageComponentType.ThreadBody
+        delegate: ThreadBodyComponent {
+            onSelectedTextChanged: selectedText => {
+                root.selectedTextChanged(selectedText);
+            }
+            onHoveredLinkChanged: hoveredLink => {
+                root.hoveredLinkChanged(hoveredLink);
+            }
+        }
+    }
+}