Add disable send policy (#1130)

* 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

src/Core/IdentityServer/ClientStore.cs

@@ -9,6 +9,7 @@ using IdentityModel;
 using Bit.Core.Utilities;
 using System.Security.Claims;
 using Bit.Core.Services;
+using Bit.Core.Context;
 using System.Collections.ObjectModel;
 
 namespace Bit.Core.IdentityServer
@@ -21,7 +22,7 @@ namespace Bit.Core.IdentityServer
         private readonly GlobalSettings _globalSettings;
         private readonly StaticClientStore _staticClientStore;
         private readonly ILicensingService _licensingService;
-        private readonly CurrentContext _currentContext;
+        private readonly ICurrentContext _currentContext;
         private readonly IOrganizationUserRepository _organizationUserRepository;
 
         public ClientStore(
@@ -31,7 +32,7 @@ namespace Bit.Core.IdentityServer
             GlobalSettings globalSettings,
             StaticClientStore staticClientStore,
             ILicensingService licensingService,
-            CurrentContext currentContext,
+            ICurrentContext currentContext,
             IOrganizationUserRepository organizationUserRepository)
         {
             _installationRepository = installationRepository;