Custom environment variables UI and implementation

Signed-off-by: TheKodeToad <TheKodeToad@proton.me>

launcher/ui/widgets/EnvironmentVariables.h

@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-3.0-only
+/*
+ *  Prism Launcher - Minecraft Launcher
+ *  Copyright (C) 2023 TheKodeToad <TheKodeToad@proton.me>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, version 3.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#include <QMap>
+#include <QWidget>
+
+namespace Ui {
+class EnvironmentVariables;
+}
+
+class EnvironmentVariables : public QWidget {
+    Q_OBJECT
+
+   public:
+    explicit EnvironmentVariables(QWidget* state = nullptr);
+    ~EnvironmentVariables() override;
+    void initialize(bool instance, bool checked, bool override, const QMap<QString, QVariant>& value);
+    bool eventFilter(QObject* watched, QEvent* event) override;
+
+    void retranslate();
+    bool checked() const;
+    bool override() const;
+    QMap<QString, QVariant> value() const;
+
+   private:
+    Ui::EnvironmentVariables* ui;
+};