When AWS credentials are not set, warn and terminate the program.

[S-mishina]

intro

If the program is executed without the current credential, it will terminate abnormally.
This should be corrected so that the program terminates normally.

➜ p_terraformer datadog aws_secret -p dev --resource dashboard --resource_id hogehoge
Traceback (most recent call last):
  File "/usr/local/bin/p_terraformer", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/usr/local/lib/python3.11/site-packages/p_terraformer/cli.py", line 27, in main
    datadog_cmd(args)
  File "/usr/local/lib/python3.11/site-packages/p_terraformer/cmd/datadog_generator.py", line 12, in datadog_cmd
    datadog_resources_output(args)
  File "/usr/local/lib/python3.11/site-packages/p_terraformer/cmd/datadog_generator.py", line 36, in datadog_resources_output
    api_key = aws_secret_get(result[0]["api_key"], "api_key", args.region)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/p_terraformer/config/cli_conf.py", line 34, in aws_secret_get
    get_secret_value_response = client.get_secret_value(
                                ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/client.py", line 530, in _api_call
    return self._make_api_call(operation_name, kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/client.py", line 943, in _make_api_call
    http, parsed_response = self._make_request(
                            ^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/client.py", line 966, in _make_request
    return self._endpoint.make_request(operation_model, request_dict)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/endpoint.py", line 119, in make_request
    return self._send_request(request_dict, operation_model)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/endpoint.py", line 198, in _send_request
    request = self.create_request(request_dict, operation_model)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/endpoint.py", line 134, in create_request
    self._event_emitter.emit(
  File "/usr/local/lib/python3.11/site-packages/botocore/hooks.py", line 412, in emit
    return self._emitter.emit(aliased_event_name, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/hooks.py", line 256, in emit
    return self._emit(event_name, kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/hooks.py", line 239, in _emit
    response = handler(**kwargs)
               ^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/signers.py", line 105, in handler
    return self.sign(operation_name, request)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/botocore/signers.py", line 189, in sign
    auth.add_auth(request)
  File "/usr/local/lib/python3.11/site-packages/botocore/auth.py", line 418, in add_auth
    raise NoCredentialsError()
botocore.exceptions.NoCredentialsError: Unable to locate credentials