Added Hardcore Warning Widget

This widget will be used in several places to notify the player that a feature has been disabled because hardcore mode is on. It includes a button to open the Achievement Settings so that Hardcore Mode may be turned off. Also included is the framework required to open AchievementsWindow specifically on the Settings tab.

Source/Core/DolphinQt/Config/HardcoreWarningWidget.cpp

@@ -0,0 +1,62 @@
+// Copyright 2023 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#ifdef USE_RETRO_ACHIEVEMENTS
+#include "DolphinQt/Config/HardcoreWarningWidget.h"
+
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QPixmap>
+#include <QPushButton>
+#include <QStyle>
+
+#include "Core/Config/AchievementSettings.h"
+#include "Core/ConfigManager.h"
+#include "Core/Core.h"
+
+#include "DolphinQt/Settings.h"
+
+HardcoreWarningWidget::HardcoreWarningWidget(QWidget* parent) : QWidget(parent)
+{
+  CreateWidgets();
+  ConnectWidgets();
+
+  connect(&Settings::Instance(), &Settings::EmulationStateChanged, this, [this] { Update(); });
+
+  Update();
+}
+
+void HardcoreWarningWidget::CreateWidgets()
+{
+  const auto size = 1.5 * QFontMetrics(font()).height();
+
+  QPixmap warning_icon = style()->standardIcon(QStyle::SP_MessageBoxWarning).pixmap(size, size);
+
+  auto* icon = new QLabel;
+  icon->setPixmap(warning_icon);
+
+  m_text = new QLabel(tr("This feature is disabled in hardcore mode."));
+  m_settings_button = new QPushButton(tr("Achievement Settings"));
+
+  auto* layout = new QHBoxLayout;
+
+  layout->addWidget(icon);
+  layout->addWidget(m_text, 1);
+  layout->addWidget(m_settings_button);
+
+  layout->setContentsMargins(0, 0, 0, 0);
+
+  setLayout(layout);
+}
+
+void HardcoreWarningWidget::ConnectWidgets()
+{
+  connect(m_settings_button, &QPushButton::clicked, this,
+          &HardcoreWarningWidget::OpenAchievementSettings);
+}
+
+void HardcoreWarningWidget::Update()
+{
+  setHidden(!Config::Get(Config::RA_HARDCORE_ENABLED));
+}
+#endif  // USE_RETRO_ACHIEVEMENTS