created a Cart service which encapsulates paying for the cart via the 3 available payment methods (vs having that code be spread over 2 files without much structure)
return values/error reporting is now consistent across all 3 payment methods
made some parameter names consistent as well
the Cart service is usable by an api controller
added a helper to retrieve payment methods by type and a Site service to house it
other helpers moved to services to clearly indicate dependencies, or lack thereof
I tested the stripe path, we no longer use paypal/authorize.net paths
In this PR: