[Other] Add a interface to get all pretrained models available from hub model server

[rainyfly]

PR types(PR类型)

Other

Description

1. add a interface: fd.get_model_list

def get_model_list(category: str=None):
    '''
    Get all pre-trained models information supported by fd.download_model.
    Args:
        category(str): model category, if None, list all models in all categories.
    Returns:
        results(dict): a dictionary, key is category, value is a list which contains models information.
    '''

2. delete temp archive file when download pretrained model with paddle format