add SDL_AppInit argument parser

[drakbar]

Added function to convert the c strings passed into SDL_AppInit to python strings. It seems like a pretty common use case that is worth implemented.

minimal example:

import os, ctypes

os.environ["SDL_MAIN_USE_CALLBACKS"] = "1"

import sdl3

def SDL_AppInit(appstate: sdl3.LP_c_void_p, argc: ctypes.c_int, argv: sdl3.LP_c_char_p) -> sdl3.SDL_AppResult:
    args = sdl3.SDL_PARSE_ARGUMENTS(argc, argv)

    for i, arg in enumerate(args):
        sdl3.SDL_LOGGER.Log(sdl3.SDL_LOGGER.Info, f"Arg[{i}]: {arg}")
    
    return sdl3.SDL_APP_FAILURE

def SDL_AppEvent(appstate: ctypes.c_void_p, event: sdl3.LP_SDL_Event) -> sdl3.SDL_AppResult:
    ...

def SDL_AppIterate(appstate: ctypes.c_void_p) -> sdl3.SDL_AppResult:
    ...

def SDL_AppQuit(appstate: ctypes.c_void_p, result: sdl3.SDL_AppResult) -> None:
    ...

[Aermoss]

Merged it, thanks!

[drakbar]

@Aermoss Not a problem. Also awesome job on this repo. I look forward to the shader_cross additions!