Adds a service account signing key to the HostedCluster spec. If specified,
we skip reconciling discovery documents to an S3 bucket.

This allows consumers of our API to generate their own signing key and
place OIDC discovery documents wherever they like.

Currently the KubeAPIServerParams are constructed with the API Server
address from the HCP status. This modifies reconciliation to use the
InfraStatus to obtain the API Server address.

Currently, global configuration of HostedClusters needs to be specified
as an arbitrary list of RawExtensions. This forces users to have to
properly specify kind and apiVersion on basic configuration resources.
In addition to that, redundant information needs to be provided as a
list of secret and configmap references.

This change simplifies hosted cluster configuration by including
specific fields for each configuration resource's spec. The user has
now explicit fields where they can specify configuration for their
cluster.

This is done before anything else to prevent other update calls from failing if e.g. they are missing a new required field.

…rlier

Enables support for IPv6 in HostedCluster API. Deprecates existing
scalar values and replaces them with slices that mirror network
settings in InstallConfig.

Replaces individual fields for networking in the HostedControlPlane spec
with the networking struct of the HostedCluster spec.