Properly support enum Names in resources

[Porges]

Naming changes

Don't convert all resource Spec Name properties to string, and instead allow the following cases:

• An enum with one value generates no AzureName property in the CRD as it cannot be changed. An AzureName() function is provided for ConvertToArm to invoke, which returns the fixed value.
  This only triggers for one resource currently:

  • Web HostingEnvironmentsMultiRolePool which must have a name of default

• An enum with multiple values generates an AzureName property with an enum value. An AzureName() function is provided for ConvertToArm which casts the enum value to string.
  Example resources for this are:

  • Keyvault VaultsAccessPolicies which allows names of add, remove, and replace
  • API Management ServiceIdentityProvider which allows names of aad, aadB2C, facebook, google, microsoft, and twitter

All Spec Name properties are still converted to string for the corresponding ARM type, as we need to insert a full ARM ID including owning resource IDs, etc.

Serialization changes

Split ArmTransformer interface into two parts FromArmConverter/ToArmConverter and make it so that Status types only implement FromArmConverter.

Other cases

There are other cases to be solved; some services (like Storage) require a Name ending in default (which is actually more correct, as the Name is a full URI including parent resources). At the schema level this is enforced via a regex like ^.*/default$. We can recognize these cases and handle them; but that will be a different PR—we don’t yet support type validation properly.

[coveralls]

Coverage increased (+22.08%) to 70.718% when pulling b62d84e on the-resource-named-default into 7e55f85 on master.

[matthchr]

Left some comments, but looks good

[matthchr]

You could make WithKubernetesResourceInterfaceImpl return a triplet with one return being an optional updated SpecType. It makes it a bit more obvious from the function signature that there's a possible modification? Or if the triplet result is too ugly you could make a little struct for it.

It's honestly not lots better but might be a bit better.