OPSAPS-31990 Add dfsServices to the python API

Added list_dfs_services to endpoints/cluster.py's ApiCluster, to match API addition in OPSAPS-31495.

Testing:
- new unit test
- verified with manual test against CM via a simple test script:

---

    from cm_api.api_client import ApiResource

    api=ApiResource("nightly-1.vpc.cloudera.com", username="foo", password="bar")
    cluster=api.get_cluster("Cluster 1")
    apiList=cluster.list_dfs_services(view="export")
    print ("%s" %(apiList))
---

(cherry picked from commit adef14d)
(cherry picked from commit e40c6259f119cc9067db9d03b092ad0e72ac5f14)

Author: Jayesh Seshadri

python/src/cm_api/endpoints/clusters.py

@@ -620,3 +620,15 @@ def export(self, export_auto_config=False):
 
     return self._get("export", ApiClusterTemplate, False,
                      params=dict(exportAutoConfig=export_auto_config), api_version=12)
+
+  def list_dfs_services(self, view=None):
+    """
+    List available DFS (distributed file system) services in a cluster.
+    @param view: View to materialize
+    @return: List of available distributed file system services in the cluster.
+    @since: API v12
+    """
+    if view:
+      return self._get_resource_root().get("%s/%s?view=%s" % (self._path(), 'dfsServices', view))
+    else:
+      return self._get_resource_root().get("%s/%s" % (self._path(), 'dfsServices'))

python/src/cm_api_tests/test_clusters.py

@@ -114,3 +114,18 @@ def test_export_cluster_template(self):
       params=dict(exportAutoConfig=True),
       retdata=ApiClusterTemplate(resource).to_json_dict())
     cluster.export(export_auto_config=True)
+
+  def test_list_dfs_services(self):
+    resource = utils.MockResource(self)
+    cluster = ApiCluster(resource, name="foo")
+    data = None
+    resource.expect("GET", "/clusters/foo/dfsServices",
+        data=data,
+        retdata={ 'name' : 'foo'})
+    cluster.list_dfs_services()
+
+    data = None
+    resource.expect("GET", "/clusters/foo/dfsServices?view=EXPORT",
+        data=data,
+        retdata={ 'name' : 'foo'})
+    cluster.list_dfs_services(view="EXPORT")