Before this change, we used the `fosite.DefaultOpenIDConnectClient{}` struct, which implements the `fosite.Client` and `fosite.OpenIDConnectClient` interfaces. For a future change, we also need to implement some additional optional interfaces, so we can no longer use the provided default types. Instead, we now use a custom `clientregistry.Client{}` struct, which implements all the requisite interfaces and can be extended to handle the new functionality (in a future change).
There is also a new `clientregistry.StaticRegistry{}` struct, which implements the `fosite.ClientManager` and looks up our single static client. We could potentially extend this in the future with a registry backed by Kubernetes API, for example.
This should be 100% refactor, with no user-observable change.
Signed-off-by: Matt Moyer <moyerm@vmware.com>
