* Implement dismiss expired cases repeating task
I have the time temporarily set to every 1 minute for testing purposes
* Rename cases list variable to be a bit more self documenting
* Switch repeat interval to four hours
* Make no operation log a debug
* Add case expiration unit tests
I called the file ModerationTests in case we want to add more general moderation unit tests in the future
* I blame zaprit
* Fix tests
* Tests nitpicks and use UtcNow instead of Now
* Use Assert.Null and Assert.NotNull for better readability
