Remove delegates

[fpseverino]

• Completely remove the delegates and move their methods to PassDataModel and OrderDataModel
• Provide a default implementation for the model middleware of PassDataModel and OrderDataModel
• Update DocC

⚠️ This PR removes the possibility for the user to make a serious mistake, below it is explained why:

Made data models generic parameters of services

Now PassesService and OrdersService require respectively PassDataModel and OrderDataModel as generic parameters (until now the data model protocols were basically useless).

That means that the user must create a service for each data model; the reason is explained in the next paragraph

Eliminate a possible error with signing passes/orders

PassDataModel and OrderDataModel now also require a typeIdentifier static property.

Each certificate Apple gives is related to a type identifier, and should only sign passes/orders of that type identifier.

Until now it was possible to sign passes and orders of different type identifiers with the same service (and therefore the same certificate).

Now each service has a single data model as a generic parameter, so this error is impossible

[0xTim]

One comment

[0xTim]

Is this best practice?

[fpseverino]

Personally I prefer not to hard code it so as not to leak it into version control, just to be safe. It's not actually strictly secret, so you might as well hard code it.