Do not blow up if no network is available

[mgxd]

In cases where we simulate no network connection, we should fail gracefully (and silently)

File "/opt/conda/bin/nibabies", line 8, in <module>
    sys.exit(main())
  File "/opt/conda/lib/python3.9/site-packages/nibabies/cli/run.py", line 28, in main
    ping_migas()
  File "/opt/conda/lib/python3.9/site-packages/nibabies/utils/misc.py", line 135, in ping_migas
    res = migas.add_project(
  File "/opt/conda/lib/python3.9/site-packages/migas/config.py", line 44, in can_send
    return func(*args, **kwargs)
  File "/opt/conda/lib/python3.9/site-packages/migas/operations.py", line 135, in add_project
    _, response = request(Config.endpoint, query)
  File "/opt/conda/lib/python3.9/site-packages/migas/request.py", line 34, in request
    conn.request("POST", purl.path, body, headers)
  File "/opt/conda/lib/python3.9/http/client.py", line 1285, in request
    self._send_request(method, url, body, headers, encode_chunked)
  File "/opt/conda/lib/python3.9/http/client.py", line 1331, in _send_request
    self.endheaders(body, encode_chunked=encode_chunked)
  File "/opt/conda/lib/python3.9/http/client.py", line 1280, in endheaders
    self._send_output(message_body, encode_chunked=encode_chunked)
  File "/opt/conda/lib/python3.9/http/client.py", line 1040, in _send_output
    self.send(msg)
  File "/opt/conda/lib/python3.9/http/client.py", line 980, in send
    self.connect()
  File "/opt/conda/lib/python3.9/http/client.py", line 1447, in connect
    super().connect()
  File "/opt/conda/lib/python3.9/http/client.py", line 946, in connect
    self.sock = self._create_connection(
  File "/opt/conda/lib/python3.9/socket.py", line 823, in create_connection
    for res in getaddrinfo(host, port, 0, SOCK_STREAM):
  File "/opt/conda/lib/python3.9/socket.py", line 954, in getaddrinfo
    for res in _socket.getaddrinfo(host, port, family, type, proto, flags):
socket.gaierror: [Errno -3] Temporary failure in name resolution