Add payload base classes to prepare for simplifying the client

This change adds payload request and response base classes to
prepare for future simplification updates to the current client
architecture. No new tests are required for this change.

kmip/core/messages/payloads/signature_verify.py

@@ -19,9 +19,10 @@ from kmip.core import attributes
 from kmip.core import enums
 from kmip.core import primitives
 from kmip.core import utils
+from kmip.core.messages.payloads import base
 
 
-class SignatureVerifyRequestPayload(primitives.Struct):
+class SignatureVerifyRequestPayload(base.RequestPayload):
     """
     A request payload for the SignatureVerify operation.
 
@@ -77,9 +78,7 @@ class SignatureVerifyRequestPayload(primitives.Struct):
                 not the payload is the last in a series for a multi-payload
                 operation. Optional, defaults to None.
         """
-        super(SignatureVerifyRequestPayload, self).__init__(
-            enums.Tags.REQUEST_PAYLOAD
-        )
+        super(SignatureVerifyRequestPayload, self).__init__()
 
         self._unique_identifier = None
         self._cryptographic_parameters = None
@@ -438,7 +437,7 @@ class SignatureVerifyRequestPayload(primitives.Struct):
         })
 
 
-class SignatureVerifyResponsePayload(primitives.Struct):
+class SignatureVerifyResponsePayload(base.ResponsePayload):
     """
     A response payload for the SignatureVerify operation.
 
@@ -472,9 +471,7 @@ class SignatureVerifyResponsePayload(primitives.Struct):
                 value, allowing the linking together of individual payloads
                 for a single overarching operation. Optional, defaults to None.
         """
-        super(SignatureVerifyResponsePayload, self).__init__(
-            enums.Tags.RESPONSE_PAYLOAD
-        )
+        super(SignatureVerifyResponsePayload, self).__init__()
 
         self._unique_identifier = None
         self._validity_indicator = None