Duffy client should handle HTTP errors gracefully

[mrc0mmand]

This is somewhat related to #523, as it causes this issue to pop up quite often, but the duffy client should handle non-successful HTTP codes instead of throwing exceptions around, to make it consistent with the rest of the DuffyAPIErrorModel:

2022-08-05 09:30:42,932 [agent-control/allocate_node] INFO: Attempting to allocate a node from pool metal-seamicro-large-centos-8s-x86_64
2022-08-05 09:30:43,446 [agent-control/main] ERROR: Execution failed
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/duffy/client/main.py", line 101, in _query_method
    return DuffyAPIErrorModel(error=response.json())
  File "/usr/local/lib/python3.8/site-packages/httpx/_models.py", line 743, in json
    return jsonlib.loads(self.text, **kwargs)
  File "/usr/lib64/python3.8/json/__init__.py", line 357, in loads
    return _default_decoder.decode(s)
  File "/usr/lib64/python3.8/json/decoder.py", line 337, in decode
    obj, end = self.raw_decode(s, idx=_w(s, 0).end())
  File "/usr/lib64/python3.8/json/decoder.py", line 355, in raw_decode
    raise JSONDecodeError("Expecting value", s, err.value) from None
json.decoder.JSONDecodeError: Expecting value: line 1 column 1 (char 0)

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "./agent-control.py", line 315, in main
    node = ac.allocate_node(args.pool)
  File "./agent-control.py", line 59, in allocate_node
    result = self._client.request_session([payload])
  File "/usr/local/lib/python3.8/site-packages/duffy/client/main.py", line 123, in request_session
    return self._query_method(
  File "/usr/local/lib/python3.8/site-packages/duffy/client/main.py", line 103, in _query_method
    response.raise_for_status()
  File "/usr/local/lib/python3.8/site-packages/httpx/_models.py", line 736, in raise_for_status
    raise HTTPStatusError(message, request=request, response=self)
httpx.HTTPStatusError: Server error '500 Internal Server Error' for url 'https://duffy.ci.centos.org/api/v1/sessions'
For more information check: https://httpstatuses.com/500

Ideally it should fill the DuffyAPIErrorModel with the HTTP status error details and pass it down as usual, to make error handling consistent.

[mrc0mmand]

This should maybe also get handled somewhat more gracefully:

2022-08-09 05:29:53,328 [agent-control/allocate_node] INFO: Attempting to allocate a node from pool virt-one-medium-centos-8s-ppc64le
2022-08-09 05:29:58,349 [agent-control/main] ERROR: Execution failed
Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/httpcore/_exceptions.py", line 8, in map_exceptions
    yield
  File "/usr/local/lib/python3.8/site-packages/httpcore/backends/sync.py", line 26, in read
    return self._sock.recv(max_bytes)
  File "/usr/lib64/python3.8/ssl.py", line 1226, in recv
    return self.read(buflen)
  File "/usr/lib64/python3.8/ssl.py", line 1101, in read
    return self._sslobj.read(len)
socket.timeout: The read operation timed out

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.8/site-packages/httpx/_transports/default.py", line 60, in map_httpcore_exceptions
    yield
  File "/usr/local/lib/python3.8/site-packages/httpx/_transports/default.py", line 218, in handle_request
    resp = self._pool.handle_request(req)
  File "/usr/local/lib/python3.8/site-packages/httpcore/_sync/connection_pool.py", line 253, in handle_request
    raise exc
  File "/usr/local/lib/python3.8/site-packages/httpcore/_sync/connection_pool.py", line 237, in handle_request
    response = connection.handle_request(request)
  File "/usr/local/lib/python3.8/site-packages/httpcore/_sync/connection.py", line 90, in handle_request
    return self._connection.handle_request(request)
  File "/usr/local/lib/python3.8/site-packages/httpcore/_sync/http11.py", line 105, in handle_request
    raise exc
  File "/usr/local/lib/python3.8/site-packages/httpcore/_sync/http11.py", line 84, in handle_request
    ) = self._receive_response_headers(**kwargs)
  File "/usr/local/lib/python3.8/site-packages/httpcore/_sync/http11.py", line 148, in _receive_response_headers
    event = self._receive_event(timeout=timeout)
  File "/usr/local/lib/python3.8/site-packages/httpcore/_sync/http11.py", line 177, in _receive_event
    data = self._network_stream.read(
  File "/usr/local/lib/python3.8/site-packages/httpcore/backends/sync.py", line 26, in read
    return self._sock.recv(max_bytes)
  File "/usr/lib64/python3.8/contextlib.py", line 131, in __exit__
    self.gen.throw(type, value, traceback)
  File "/usr/local/lib/python3.8/site-packages/httpcore/_exceptions.py", line 12, in map_exceptions
    raise to_exc(exc)
httpcore.ReadTimeout: The read operation timed out

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "./agent-control.py", line 330, in main
    ac.allocate_node(args.pool)
  File "./agent-control.py", line 69, in allocate_node
    result = self._client.request_session([payload])
  File "/usr/local/lib/python3.8/site-packages/duffy/client/main.py", line 123, in request_session
    return self._query_method(
  File "/usr/local/lib/python3.8/site-packages/duffy/client/main.py", line 94, in _query_method
    response = client_method(url=url, **add_kwargs)
  File "/usr/local/lib/python3.8/site-packages/httpx/_client.py", line 1130, in post
    return self.request(
  File "/usr/local/lib/python3.8/site-packages/httpx/_client.py", line 815, in request
    return self.send(request, auth=auth, follow_redirects=follow_redirects)
  File "/usr/local/lib/python3.8/site-packages/httpx/_client.py", line 902, in send
    response = self._send_handling_auth(
  File "/usr/local/lib/python3.8/site-packages/httpx/_client.py", line 930, in _send_handling_auth
    response = self._send_handling_redirects(
  File "/usr/local/lib/python3.8/site-packages/httpx/_client.py", line 967, in _send_handling_redirects
    response = self._send_single_request(request)
  File "/usr/local/lib/python3.8/site-packages/httpx/_client.py", line 1003, in _send_single_request
    response = transport.handle_request(request)
  File "/usr/local/lib/python3.8/site-packages/httpx/_transports/default.py", line 218, in handle_request
    resp = self._pool.handle_request(req)
  File "/usr/lib64/python3.8/contextlib.py", line 131, in __exit__
    self.gen.throw(type, value, traceback)
  File "/usr/local/lib/python3.8/site-packages/httpx/_transports/default.py", line 77, in map_httpcore_exceptions
    raise mapped_exc(message) from exc
httpx.ReadTimeout: The read operation timed out