create gr:make_root_type task

This is intended to be used for summer project applications, which we want to make root-level entities.
don’t do actual ‘puts’ calls during tests
change to a constant
modify endpoint to create subscriptions in SNS

Don’t track subscriptions internally.
add a “gr_” prefix to SNS topics
add a regex validator to EntityType#name

The name is used to create SNS topics, so it needs to adhere to SNS topic name restrictions.
The tests in this commit don’t seem to work; I’m not sure why.  They are disabled for now.
fix broken validations tests
extract name validation rules into its own validator
id is needed
add a sns_subscribe task to check subscription code