OPEN - issue CORE-4294: Donkey: Create pass through endpoint to mark
receipt of system messages 
https://pods.iplantcollaborative.org/jira/browse/CORE-4294

The notification agent end points map as follows:

/system/new-messages -> /secured/notifications/system/new-messages
/system/received -> /secured/notifications/system/received
Merge branch 'dev' into donkzilla