Provide a wrapper for get_next_parameter() to update namespace automatically

[ultmaster]

Suggest to provide this function in SDK, as in most of the cases, when users receive a parameter, they are going to replace the corresponding argument.

def update_args(args):
    # args is obtained by `parser.parse_args()`
    params = nni.get_next_parameter()
    if not params:
        params = {}
    if params:
        for k, v in params.items():
            assert hasattr(namespace, k), "Args doesn't have received key: %s" % k
            assert type(getattr(namespace, k)) == type(v), "Received key has different type"
            setattr(namespace, k, v)

[ultmaster]

Done