Move NeoChatConnection and NeoChatRoom to LibNeoChat

Move `NeoChatConnection` and `NeoChatRoom` to `LibNeoChat` along with any required dependencies.

src/libneochat/roomlastmessageprovider.cpp

@@ -0,0 +1,38 @@
+// SPDX-FileCopyrightText: 2023 Carl Schwan <carl@carlschwan.eu>
+// SPDX-License-Identifier: LGPL-2.0-or-later
+
+#include "roomlastmessageprovider.h"
+
+using namespace Qt::Literals::StringLiterals;
+
+RoomLastMessageProvider::RoomLastMessageProvider()
+    : m_config(KSharedConfig::openStateConfig())
+    , m_configGroup(KConfigGroup(m_config, u"EventCache"_s))
+{
+}
+
+RoomLastMessageProvider::~RoomLastMessageProvider()
+{
+    m_config->sync();
+}
+
+RoomLastMessageProvider &RoomLastMessageProvider::self()
+{
+    static RoomLastMessageProvider instance;
+    return instance;
+}
+
+bool RoomLastMessageProvider::hasKey(const QString &roomId) const
+{
+    return m_configGroup.hasKey(roomId);
+}
+
+QByteArray RoomLastMessageProvider::read(const QString &roomId) const
+{
+    return m_configGroup.readEntry(roomId, QByteArray{});
+}
+
+void RoomLastMessageProvider::write(const QString &roomId, const QByteArray &json)
+{
+    m_configGroup.writeEntry(roomId, json);
+}