Add initial implementation of ConnectTool with Dear ImGui and Steam Networking

- Created project files for ConnectTool including filters and user settings.
- Added README.md with setup instructions and prerequisites for building the project.
- Implemented imgui_hello.cpp as a simple Dear ImGui application using GLFW and OpenGL.
- Developed online_game_tool.cpp for hosting and joining game rooms using Steam Networking.
- Created p2p_chat.cpp for a peer-to-peer chat application utilizing Steam Networking.
- Implemented steam_friends.cpp to display the user's Steam friends list.
- Added TCP client and server classes for handling network communication.
- Integrated TCP server and client functionality into online_game_tool for real-time data exchange.

imgui_hello.cpp

@@ -0,0 +1,72 @@
+#include <GLFW/glfw3.h>
+#include <imgui.h>
+#include <imgui_impl_glfw.h>
+#include <imgui_impl_opengl3.h>
+#include <iostream>
+
+int main() {
+    // Initialize GLFW
+    if (!glfwInit()) {
+        std::cerr << "Failed to initialize GLFW" << std::endl;
+        return -1;
+    }
+
+    // Create window
+    GLFWwindow* window = glfwCreateWindow(1280, 720, "Dear ImGui Hello World", nullptr, nullptr);
+    if (!window) {
+        std::cerr << "Failed to create GLFW window" << std::endl;
+        glfwTerminate();
+        return -1;
+    }
+    glfwMakeContextCurrent(window);
+    glfwSwapInterval(1); // Enable vsync
+
+    // Initialize ImGui
+    IMGUI_CHECKVERSION();
+    ImGui::CreateContext();
+    ImGuiIO& io = ImGui::GetIO();
+    (void)io;
+    ImGui::StyleColorsDark();
+
+    // Initialize ImGui backends
+    ImGui_ImplGlfw_InitForOpenGL(window, true);
+    ImGui_ImplOpenGL3_Init("#version 130");
+
+    // Main loop
+    while (!glfwWindowShouldClose(window)) {
+        // Poll events
+        glfwPollEvents();
+
+        // Start ImGui frame
+        ImGui_ImplOpenGL3_NewFrame();
+        ImGui_ImplGlfw_NewFrame();
+        ImGui::NewFrame();
+
+        // Create a simple window
+        ImGui::Begin("Hello, World!");
+        ImGui::Text("Welcome to Dear ImGui!");
+        ImGui::Text("Application average %.3f ms/frame (%.1f FPS)", 1000.0f / io.Framerate, io.Framerate);
+        ImGui::End();
+
+        // Rendering
+        ImGui::Render();
+        int display_w, display_h;
+        glfwGetFramebufferSize(window, &display_w, &display_h);
+        glViewport(0, 0, display_w, display_h);
+        glClearColor(0.45f, 0.55f, 0.60f, 1.00f);
+        glClear(GL_COLOR_BUFFER_BIT);
+        ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());
+
+        // Swap buffers
+        glfwSwapBuffers(window);
+    }
+
+    // Cleanup
+    ImGui_ImplOpenGL3_Shutdown();
+    ImGui_ImplGlfw_Shutdown();
+    ImGui::DestroyContext();
+    glfwDestroyWindow(window);
+    glfwTerminate();
+
+    return 0;
+}