Move the storage of MessageContentModels to the room

Move the storage of MessageContentModels to the room in the same manner as memeber objects to prevent duplication but mainly to make the system easier to maintain going forward with things like threads for example. This requires the creation of a MessageContentFilterModel as the same model may be used in multiple places, sometimes with the author showning sometimes not.

src/models/messagecontentfiltermodel.cpp

@@ -0,0 +1,37 @@
+// SPDX-FileCopyrightText: 2025 James Graham <james.h.graham@protonmail.com>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#include "messagecontentfiltermodel.h"
+#include "enums/messagecomponenttype.h"
+#include "models/messagecontentmodel.h"
+
+MessageContentFilterModel::MessageContentFilterModel(QObject *parent)
+    : QSortFilterProxyModel(parent)
+{
+}
+
+bool MessageContentFilterModel::showAuthor() const
+{
+    return m_showAuthor;
+}
+
+void MessageContentFilterModel::setShowAuthor(bool showAuthor)
+{
+    if (showAuthor == m_showAuthor) {
+        return;
+    }
+
+    m_showAuthor = showAuthor;
+    Q_EMIT showAuthorChanged();
+}
+
+bool MessageContentFilterModel::filterAcceptsRow(int source_row, const QModelIndex &source_parent) const
+{
+    if (m_showAuthor) {
+        return true;
+    }
+
+    const auto index = sourceModel()->index(source_row, 0, source_parent);
+    auto contentType = static_cast<MessageComponentType::Type>(index.data(MessageContentModel::ComponentTypeRole).toInt());
+    return contentType != MessageComponentType::Author;
+}