[AIRFLOW-2524] Update SageMaker hook and operators (apache#4091)

This re-works the SageMaker functionality in Airflow to be more complete, and more useful for the kinds of operations that SageMaker supports.

We removed some files and operators here, but these were only added after the last release so we don't need to worry about any sort of back-compat.

airflow/contrib/hooks/aws_hook.py

@@ -17,7 +17,6 @@
 # specific language governing permissions and limitations
 # under the License.
 
-
 import boto3
 import configparser
 import logging
@@ -164,17 +163,17 @@ def _get_credentials(self, region_name):
             aws_session_token=aws_session_token,
             region_name=region_name), endpoint_url
 
-    def get_client_type(self, client_type, region_name=None):
+    def get_client_type(self, client_type, region_name=None, config=None):
         session, endpoint_url = self._get_credentials(region_name)
 
         return session.client(client_type, endpoint_url=endpoint_url,
-                              verify=self.verify)
+                              config=config, verify=self.verify)
 
-    def get_resource_type(self, resource_type, region_name=None):
+    def get_resource_type(self, resource_type, region_name=None, config=None):
         session, endpoint_url = self._get_credentials(region_name)
 
         return session.resource(resource_type, endpoint_url=endpoint_url,
-                                verify=self.verify)
+                                config=config, verify=self.verify)
 
     def get_session(self, region_name=None):
         """Get the underlying boto3.session."""
@@ -191,3 +190,16 @@ def get_credentials(self, region_name=None):
         # secret key separately can lead to a race condition.
         # See https://stackoverflow.com/a/36291428/8283373
         return session.get_credentials().get_frozen_credentials()
+
+    def expand_role(self, role):
+        """
+        Expand an IAM role name to an IAM role ARN. If role is already an IAM ARN,
+        no change is made.
+
+        :param role: IAM role name or ARN
+        :return: IAM role ARN
+        """
+        if '/' in role:
+            return role
+        else:
+            return self.get_client_type('iam').get_role(RoleName=role)['Role']['Arn']