Add OIDC Issuer/Provider to status field

[adammw]

trafficstars

/kind feature /area provider/eks

Describe the solution you'd like A status field populated upon Cluster creation detailing the OIDC issuer/identity for the cluster which is required to make IAM trust policies for IRSA.

Anything else you would like to add: The provider already fetches and uses this information for the associateOIDCProvider feature.

The issuer can also be 'guessed' from the controlPlaneEndpoint as it uses a common form: https://oidc.eks.us-west-2.amazonaws.com/id/<ID> where <ID> is the same as the controlPlaneEndpoint ID.