Dear ImGui Implementation (#598)

* added imgui as dependency

* imgui renderer/basic input implementation

* imgui: add layers system

Add video info layer to show fps. Press F10 to toggle it.

* imgui: add custom imgui config

* imgui: gamepad capture, stopping propagation

* imgui: changed config & log file path to use portable dir

* videoout: render blank frame when video output is closed

required to render imgui even when game has no video output

- fixed merge compile-error

src/imgui/renderer/imgui_core.h

@@ -0,0 +1,31 @@
+// SPDX-FileCopyrightText: Copyright 2024 shadPS4 Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include "video_core/renderer_vulkan/vk_instance.h"
+#include "vulkan/vulkan_handles.hpp"
+
+union SDL_Event;
+
+namespace Vulkan {
+struct Frame;
+}
+
+namespace ImGui::Core {
+
+void Initialize(const Vulkan::Instance& instance, const Frontend::WindowSDL& window,
+                u32 image_count, vk::Format surface_format,
+                const vk::AllocationCallbacks* allocator = nullptr);
+
+void OnResize();
+
+void Shutdown(const vk::Device& device);
+
+bool ProcessEvent(SDL_Event* event);
+
+void NewFrame();
+
+void Render(const vk::CommandBuffer& cmdbuf, Vulkan::Frame* frame);
+
+} // namespace ImGui::Core