RelyingPartyRegistration Credentials Should Be Split by Party

[jzheaux]

Initially, RelyingPartyRegistration held both relying party and asserting party details together.

In 5.3, the asserting party details were split out into an inner class, similar to ClientRegistration.

The relying party and asserting party credentials are still listed together, and they need to be split as well in order to complete the refactor.

Generally speaking, an instance of RelyingPartyRegistration will have the asserting party's verification and encryption credentials. This allows the relying party to verify assertions and encrypt authentication requests, for example.

As such, it would make sense for RelyingPartyRegistration.ProviderDetails to hold the verification and encryption credentials while RelyingPartyRegistration continues to hold the signing and decryption credentials.

To maintain backward compatibility, it will be necessary in the builder to copy into ProviderDetails any verification or encryption credentials specified in RelyingPartyRegistration and vice-versa.