Recurly coupon page access does not respect the config setting

I converted the access check to a service, mostly to be consistent with the other ones already in the module. And added some basic tests for the setting to confirm it works.

Personally I don't think we need to implement an update hook to clear the cache. I believe it's already best practice to clear the cache whenever updating a module and deploying new code and an update hook just to clear the cache is overkill.

Automatically closed - issue fixed for 2 weeks with no activity.