It's not clear how to provide authentication details

[okainov]

1. Install the tool
2. Execute glacier vaults list
3. Exception happens

Traceback (most recent call last):
  File "C:/Python37-32/Scripts/glacier", line 161, in <module>
    main()
  File "C:/Python37-32/Scripts/glacier", line 149, in main
    list_vaults(region, access_key, secret_key)
  File "C:/Python37-32/Scripts/glacier", line 98, in list_vaults
    layer2 = connect(region, access_key = access_key, secret_key = secret_key)
  File "C:/Python37-32/Scripts/glacier", line 90, in connect
    debug=debug_level)
  File "C:\python37-32\lib\site-packages\boto\glacier\__init__.py", line 41, in connect_to_region
    return connect('glacier', region_name, connection_cls=Layer2, **kw_params)
  File "C:\python37-32\lib\site-packages\boto\regioninfo.py", line 220, in connect
    return region.connect(**kw_params)
  File "C:\python37-32\lib\site-packages\boto\regioninfo.py", line 290, in connect
    return self.connection_cls(region=self, **kw_params)
  File "C:\python37-32\lib\site-packages\boto\glacier\layer2.py", line 38, in __init__
    self.layer1 = Layer1(*args, **kwargs)
  File "C:\python37-32\lib\site-packages\boto\glacier\layer1.py", line 98, in __init__
    profile_name=profile_name)
  File "C:\python37-32\lib\site-packages\boto\connection.py", line 569, in __init__
    host, config, self.provider, self._required_auth_capability())
  File "C:\python37-32\lib\site-packages\boto\auth.py", line 1021, in get_auth_handler
    'Check your credentials' % (len(names), str(names)))
boto.exception.NoAuthHandlerFound: No handler was ready to authenticate. 1 handlers were checked. ['HmacAuthV4Handler'] Check your credentials

Please add to readme part about storing credentials and add proper error handling to the tool