refs: https://github.com/TryGhost/Team/issues/759
- wired up a matchHelper feature flag & used the labsEnabledHelper tool to gate the helper
- added a first version of the match helper, which is intended to replace the has helper
- this is an experimental helper and may or may not make it to GA
- match is a simple comparison helper, right now it does a very basic equals or not equals comparison
- much more functionality is needed to reach parity with has
