Add support for Windows platform and some bug fixes

[Morphlng]

1. Why

I'm currently using macad-gym on a Windows 11 device with the latest version of Carla (0.9.13). Seems like macad-gym does not support Windows at all, and a couple of API from Carla have whether been changed or deprecated. I've made some refractor to make things work again (mainly focusing on the multi_env.py file)

2. Changes

I've made a couple of changes as below.

2.1 Windows support

I've referred to the issue [Windows Support]module 'os' has no attribute 'getpgid' #32. The solution given in comment can indeed make the code run. However, the cleanup() function can't close up both CarlaUE4.exe and CarlaUE4-Win64-Shipping.exe (the latter is the real server which is a subprocess of the CarlaUE4.exe). So instead, I call the taskkill -F /T /PID {pid} to recursively kill all related processes.

2.2 Stuck at env.reset()

The problem addressed in Also stuck in env.reset() in example #63 is due to the failure of carla.Client() establishing connection with Carla-server. This problem is caused by two reasons:

https://github.com/praveen-palanisamy/macad-gym/blob/38884ac4bc7fb2e91a865950cff4eeadeed02f60/src/macad_gym/carla/multi_env.py#L453-L469

These lines of code starting a Carla subprocess using subprocess.Popen is incorrect, when using a list to pass arguments, each arg should be split up. I.e., ["-carla-server", "-carla-rpc-port=2000"] is ok, but ["-carla-server -carla-rpc-port=2000"] is not. This problem will cause the Carla-server not starting with the specified port.

Another thing is the Client side failed to connect to server, related code is here:

https://github.com/praveen-palanisamy/macad-gym/blob/38884ac4bc7fb2e91a865950cff4eeadeed02f60/src/macad_gym/carla/multi_env.py#L478-L487

The above code test client.get_server_version() immediately after its creation, which can lead to a race between the socket connection and communication. Simply time.sleep(2) after carla.Client() will solve the problem.

2.3 Deprecated/Changed API

1. world.tick() and world.wait_for_tick() could lead to a race condition, Fixes for synchronous mode PR has already make tick() function synchronized.
2. Carla no longer support passing map as argument in command-line since 0.9.6+. The correct way to do is using the Client-API, client.load_world(map). I've added this in init_server function.

2.4 Minor bug fixes

1. carla.WeatherParameters.cloudiness instead of carla.WeatherParameters.cloudyness
2. The cameras will get destroyed twice in function _clean_world, this doesn't affect running but will raise exceptions. I've commented out one destroy process.