When the Pinniped server has been installed with the `api_group_suffix`
option, for example using `mysuffix.com`, then clients who would like to
submit a `TokenCredentialRequest` to the server should set the
`Spec.Authenticator.APIGroup` field as `authentication.concierge.mysuffix.com`.
This makes more sense from the client's point of view than using the
default `authentication.concierge.pinniped.dev` because
`authentication.concierge.mysuffix.com` is the name of the API group
that they can observe their cluster and `authentication.concierge.pinniped.dev`
does not exist as an API group on their cluster.
This commit includes both the client and server-side changes to make
this work, as well as integration test updates.
Co-authored-by: Andrew Keesler <akeesler@vmware.com>
Co-authored-by: Ryan Richard <richardry@vmware.com>
Co-authored-by: Margo Crawford <margaretc@vmware.com>
