Extract argument list to generic string list class and widget

To be used for http header support.

src/utils/string-list.hpp

@@ -0,0 +1,49 @@
+#pragma once
+#include <obs-data.h>
+#include <obs-module.h>
+
+#include <QPushButton>
+#include <QListWidget>
+#include <QStringList>
+
+class StringList : public QStringList {
+public:
+	bool Save(obs_data_t *obj, const char *name,
+		  const char *elementName = "string") const;
+	bool Load(obs_data_t *obj, const char *name,
+		  const char *elementName = "string");
+
+	friend class StringListEdit;
+};
+
+class StringListEdit : public QWidget {
+	Q_OBJECT
+
+public:
+	StringListEdit(QWidget *parent, const QString &addString = "",
+		       const QString &addStringDescription = "");
+	void SetStringList(const StringList &);
+
+private slots:
+	void Add();
+	void Remove();
+	void Up();
+	void Down();
+	void Clicked(QListWidgetItem *);
+signals:
+	void StringListChanged(const StringList &);
+
+private:
+	void SetListSize();
+
+	StringList _stringList;
+
+	QListWidget *_list;
+	QPushButton *_add;
+	QPushButton *_remove;
+	QPushButton *_up;
+	QPushButton *_down;
+
+	QString _addString;
+	QString _addStringDescription;
+};