WIP: build(uwebsockets): add cmakelists

[Napolitain]

Suggesting a CMakeLists.txt file for easily building the project.
CMake also integrates well with vcpkg (inside IDE notably). This worked for me when building uWebSockets on Windows (with MSVC!).

ran with (through CLion) :

"D:\Program Files\Jetbrains\CLion Nova\bin\cmake\win\x64\bin\cmake.exe" -DCMAKE_BUILD_TYPE=Debug "-DCMAKE_MAKE_PROGRAM=D:/Program Files/Jetbrains/CLion Nova/bin/ninja/win/x64/ninja.exe" "-DCMAKE_C_COMPILER=D:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.39.33519/bin/Hostx64/x64/cl.exe" "-DCMAKE_CXX_COMPILER=D:/Program Files/Microsoft Visual Studio/2022/Community/VC/Tools/MSVC/14.39.33519/bin/Hostx64/x64/cl.exe" -DCMAKE_TOOLCHAIN_FILE=C:\Users\-\.vcpkg-clion\vcpkg\scripts\buildsystems\vcpkg.cmake -DWITH_LIBUV:BOOL=ON -G Ninja -S D:\Repos\- -B D:\Repos\-\cmake-build-debug
"D:\Program Files\Jetbrains\CLion Nova\bin\cmake\win\x64\bin\cmake.exe" --build D:\Repos\-\cmake-build-release --target HelloWorld -j 26

also : uNetworking/uWebSockets#1788