Fix wayland activation

Adds support for xdg_activation_v1 when calling the application from the
system tray by using KStatusNotifier which supports it.
Listens to XDG_ACTIVATION_TOKEN as it's passed when we are started from
dbus.

src/trayicon_sni.cpp

@@ -0,0 +1,25 @@
+// SPDX-FileCopyrightText: 2021 Aleix Pol Gonzalez <aleixpol@kde.org>
+// SPDX-License-Identifier: GPL-3.0-only
+
+#include "trayicon_sni.h"
+#include <KWindowSystem>
+
+TrayIcon::TrayIcon(QObject *parent)
+    : KStatusNotifierItem(parent)
+{
+    setIconByName("org.kde.neochat");
+    connect(this, &KStatusNotifierItem::activateRequested, this, [this] {
+        KWindowSystem::setCurrentXdgActivationToken(providedToken());
+        Q_EMIT showWindow();
+    });
+}
+
+void TrayIcon::show()
+{
+    setStatus(Active);
+}
+
+void TrayIcon::hide()
+{
+    setStatus(Passive);
+}