Dbs3 secure reader

Hi Yuyi,

I have implemented security also for the GET APIs of the DBSReaderModel and DBSMigrateModel. I have tested it on my dev vm and seems to work fine. In addition, I have added the view_instances.json the official repository. I will prepare changed configuration to fetch the file from the official repository instead of Diego's private one.

Could you review and merge, please?

Thanks,
Manuel