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.

ConnectTool.vcxproj.user

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="Current" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <PropertyGroup />
+</Project>