VideoCommon: add logic to read a GraphicsMod from configuration

Source/Core/VideoCommon/GraphicsModSystem/Config/GraphicsMod.h

@@ -0,0 +1,45 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <optional>
+#include <string>
+#include <vector>
+
+#include <picojson.h>
+
+#include "VideoCommon/GraphicsModSystem/Config/GraphicsModFeature.h"
+#include "VideoCommon/GraphicsModSystem/Config/GraphicsTargetGroup.h"
+
+struct GraphicsModConfig
+{
+  std::string m_title;
+  std::string m_author;
+  std::string m_description;
+  bool m_enabled = false;
+  u16 m_weight = 0;
+  std::string m_relative_path;
+
+  enum class Source
+  {
+    User,
+    System
+  };
+  Source m_source = Source::User;
+
+  std::vector<GraphicsTargetGroupConfig> m_groups;
+  std::vector<GraphicsModFeatureConfig> m_features;
+
+  static std::optional<GraphicsModConfig> Create(const std::string& file, Source source);
+  static std::optional<GraphicsModConfig> Create(const picojson::object* obj);
+
+  std::string GetAbsolutePath() const;
+
+  bool DeserializeFromConfig(const picojson::value& value);
+
+  void SerializeToProfile(picojson::object* value) const;
+  void DeserializeFromProfile(const picojson::object& value);
+
+  bool operator<(const GraphicsModConfig& other) const;
+};