Move parts of MappingCommon out of DolphinQt

Some of the functions in MappingCommon would be useful to use on
mobile in the future.

Source/Core/InputCommon/ControllerInterface/MappingCommon.h

@@ -0,0 +1,29 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "InputCommon/ControllerInterface/CoreDevice.h"
+
+namespace ciface::MappingCommon
+{
+enum class Quote
+{
+  On,
+  Off
+};
+
+std::string GetExpressionForControl(const std::string& control_name,
+                                    const ciface::Core::DeviceQualifier& control_device,
+                                    const ciface::Core::DeviceQualifier& default_device,
+                                    Quote quote = Quote::On);
+
+std::string BuildExpression(const std::vector<ciface::Core::DeviceContainer::InputDetection>&,
+                            const ciface::Core::DeviceQualifier& default_device, Quote quote);
+
+void RemoveSpuriousTriggerCombinations(std::vector<ciface::Core::DeviceContainer::InputDetection>*);
+
+}  // namespace ciface::MappingCommon