Add system to automatically switch default GFWorld depending on the context

[GsLogiMaker]

Due to how Glecs is structured, it is common to have to explicitly state in what world the user wants to be creating entities, systems, and components. This leads to code that is more verbose than it should be. For example, when registering items within modules:

extends GFModule

def _register(world:GFWorld) -> void:
    # This line requires the world to be specified, otherwise
    # the system might not be defined in the same world as the
    # module.
    GFSystemBuilder.new_in_world(world) \
        ...
        .for_each(...)
    
    # Ideally, the world would not need to be specified
    # and Glecs would infer by the context what world
    # should be used.
    GFSystemBuilder.new() \
        ...
        .for_each(...)

The solution to this needs to be multi-threading safe.