* Add Disable Send policy
* Test DisableSend policy
* PR Review
* Update tests for using CurrentContext
This required making an interface for CurrentContext and mocking out
the members used. The interface can be expanded as needed for tests.
I moved CurrentContext to a folder, which changes the namespace
and causes a lot of file touches, but most are just adding a reference
* Fix failing test
* Update exemption to include all exempt users
* Move all CurrentContext usages to ICurrentContext
* PR review. Match messaging with Web
