Add export / import functionality to macro tab

This enables the easy sharing of single / multiple macros across scene
collections.
Previously either all settings had to be copied via the export / import
functionality of the General tab or none at all.

src/utils/macro-export-import-dialog.cpp

@@ -0,0 +1,61 @@
+#include "macro-export-import-dialog.hpp"
+#include "obs-module-helper.hpp"
+
+#include <QLayout>
+#include <QLabel>
+#include <QDialogButtonBox>
+
+namespace advss {
+
+MacroExportImportDialog::MacroExportImportDialog(Type type)
+	: QDialog(nullptr), _importExportString(new QPlainTextEdit(this))
+{
+	_importExportString->setReadOnly(type == Type::EXPORT_MACRO);
+	auto label = new QLabel(obs_module_text(
+		type == Type::EXPORT_MACRO
+			? "AdvSceneSwitcher.macroTab.export.info"
+			: "AdvSceneSwitcher.macroTab.import.info"));
+	label->setWordWrap(true);
+
+	QDialogButtonBox *buttons = nullptr;
+	if (type == Type::EXPORT_MACRO) {
+		buttons = new QDialogButtonBox(QDialogButtonBox::Ok);
+	} else {
+		buttons = new QDialogButtonBox(QDialogButtonBox::Ok |
+					       QDialogButtonBox::Cancel);
+	}
+	connect(buttons, &QDialogButtonBox::accepted, this, &QDialog::accept);
+	connect(buttons, &QDialogButtonBox::rejected, this, &QDialog::reject);
+	buttons->setCenterButtons(true);
+
+	auto layout = new QVBoxLayout;
+	layout->addWidget(label);
+	layout->addWidget(_importExportString);
+	layout->addWidget(buttons);
+	setLayout(layout);
+
+	setWindowTitle(obs_module_text("AdvSceneSwitcher.windowTitle"));
+}
+
+void MacroExportImportDialog::ExportMacros(const QString &json)
+{
+	MacroExportImportDialog dialog(
+		MacroExportImportDialog::Type::EXPORT_MACRO);
+	dialog._importExportString->setPlainText(json);
+	dialog.adjustSize();
+	dialog.updateGeometry();
+	dialog.exec();
+}
+
+bool MacroExportImportDialog::ImportMacros(QString &json)
+{
+	MacroExportImportDialog dialog(
+		MacroExportImportDialog::Type::IMPORT_MACRO);
+	if (dialog.exec() == QDialog::Accepted) {
+		json = dialog._importExportString->toPlainText();
+		return true;
+	}
+	return false;
+}
+
+} // namespace advss

src/utils/macro-export-import-dialog.hpp

@@ -0,0 +1,20 @@
+#pragma once
+#include <QDialog>
+#include <QPlainTextEdit>
+
+namespace advss {
+
+class MacroExportImportDialog : public QDialog {
+	Q_OBJECT
+public:
+	enum class Type { EXPORT_MACRO, IMPORT_MACRO };
+	MacroExportImportDialog(Type type);
+
+	static void ExportMacros(const QString &json);
+	static bool ImportMacros(QString &json);
+
+private:
+	QPlainTextEdit *_importExportString;
+};
+
+} // namespace advss