[FEATURE] Enhance ease of adding additional defaults to code

Is your feature request related to a problem?

Currently for 2.13, in order to add a new default file that is attached to a use case we need to add the json file and also add the use case to an enum. This isn't too user friendly as outside users have to add this in multiple different locations. We can also explore a way to more efficiently add these defaults templates through an API for the customer to easily have their own templates in there own cluster.

What solution would you like?

Potential options are having the defaults and template all in one place, but this would still require an enum to be edited on every new template.

Having an enum also has its benefits like more likely stopping errors when a usecase name isn't attached to a file or vice versa ahead of time. We could also focus more on enhancing adding new default templates on a customer's individual cluster through an API.

No files, tests, or entry points are named. Start by locating the enum and JSON default-template registration for the 2.13 defaults, then inspect the existing customer-facing APIs before choosing between centralizing templates and adding cluster-level template management. Done is not defined because the issue presents multiple possible solutions without acceptance criteria.