Add possibility to query deb packages for host (#1233)

(cherry picked from commit 5dee74c)

nailgun/entities.py

@@ -4578,6 +4578,24 @@ def packages(self, synchronous=True, timeout=None, **kwargs):
         response = client.get(self.path('packages'), **kwargs)
         return _handle_response(response, self._server_config, synchronous, timeout)
 
+    def debs(self, synchronous=True, timeout=None, **kwargs):
+        """List debian packages installed on the host.
+
+        :param synchronous: What should happen if the server returns an HTTP
+            202 (accepted) status code? Wait for the task to complete if
+            ``True``. Immediately return the server's response otherwise.
+        :param timeout: Maximum number of seconds to wait until timing out.
+            Defaults to ``nailgun.entity_mixins.TASK_TIMEOUT``.
+        :param kwargs: Arguments to pass to requests.
+        :returns: The server's response, with all content decoded.
+        :raises: ``requests.exceptions.HTTPError`` If the server responds with
+            an HTTP 4XX or 5XX message.
+        """
+        kwargs = kwargs.copy()  # shadow the passed-in kwargs
+        kwargs.update(self._server_config.get_client_kwargs())
+        response = client.get(self.path('debs'), **kwargs)
+        return _handle_response(response, self._server_config, synchronous, timeout)
+
     def module_streams(self, synchronous=True, timeout=None, **kwargs):
         """List module_streams available for the host.
 
@@ -4840,6 +4858,7 @@ def path(self, which=None):
             'errata/applicability',
             'facts',
             'packages',
+            'debs',
             'play_roles',
             'power',
             'puppetclass_ids',