Another huge batch of registry v2 changes

Add patch support and resumeable sha
Implement all actual registry methods
Add a simple database generation option

data/model/__init__.py

@@ -9,6 +9,10 @@ class BlobDoesNotExist(DataModelException):
   pass
 
 
+class InvalidBlobUpload(DataModelException):
+  pass
+
+
 class InvalidEmailAddressException(DataModelException):
   pass
 
@@ -65,6 +69,10 @@ class InvalidTeamMemberException(DataModelException):
   pass
 
 
+class InvalidManifestException(DataModelException):
+  pass
+
+
 class TooManyLoginAttemptsException(Exception):
   def __init__(self, message, retry_after):
     super(TooManyLoginAttemptsException, self).__init__(message)