* Adds Validate class in util with accompanying regular expressions
* Provides tests for NotificationEmail and Validate.EmailAddress
* Provides default values for NotificationEmail Subject and Message
These default values resolve the underlying issue of #3021 w/out
needing to modify external sources (such as impl of IMessagingHandler)
Adds basic test coverage for default NotificationManager.
* Confirms correct notification type added to Messages
* Confirms rate limit set at 30 (unable to fully test due to hard-coded
and non-abstracted rate limit logic (could upgrade to RateGate as ctor
parameter to aid unit testing here)
Martin Molinero