Move remaining code to app module

There's still some stuff that could potentially go elsewhere but I think it's enough for now.

src/app/trayicon.cpp

@@ -0,0 +1,45 @@
+// SPDX-FileCopyrightText: 2019 Black Hat <bhat@encom.eu.org>
+// SPDX-FileCopyrightText: 2021 Nicolas Fella <nicolas.fella@gmx.de>
+// SPDX-License-Identifier: GPL-3.0-only
+
+#include "trayicon.h"
+
+#include <QCoreApplication>
+#include <QMenu>
+
+#include <KLocalizedString>
+
+#include "windowcontroller.h"
+
+using namespace Qt::StringLiterals;
+
+TrayIcon::TrayIcon(QObject *parent)
+    : QSystemTrayIcon(parent)
+{
+    setIcon(QIcon(u":/icons/org.kde.neochat.tray.svg"_s));
+    QMenu *menu = new QMenu();
+    auto viewAction_ = new QAction(i18n("Show"), parent);
+
+    connect(viewAction_, &QAction::triggered, this, [] {
+        WindowController::instance().toggleWindow();
+    });
+    connect(this, &QSystemTrayIcon::activated, this, [](QSystemTrayIcon::ActivationReason reason) {
+        if (reason == QSystemTrayIcon::Trigger) {
+            WindowController::instance().toggleWindow();
+        }
+    });
+
+    menu->addAction(viewAction_);
+
+    menu->addSeparator();
+
+    auto quitAction = new QAction(i18n("Quit"), parent);
+    quitAction->setIcon(QIcon::fromTheme(u"application-exit"_s));
+    connect(quitAction, &QAction::triggered, QCoreApplication::instance(), QCoreApplication::quit);
+
+    menu->addAction(quitAction);
+
+    setContextMenu(menu);
+}
+
+#include "moc_trayicon.cpp"