ClusterManagementAddOn and ManagedClusterAddon API v1beta1 design

[haoqing0110]

Describe the enhancement
A clear and concise description of what the enhancement request is.

v1beta1

• ClusterManagementAddOn spec.defaultConfigs
• ManagedClusterAddon status.registrations

v1alpha1 <-> v1beta1 conversion webhook

• ClusterManagementAddOn spec.supportedConfigs (v1alpha1) <-> spec.defaultConfigs (v1beta1)
• ManagedClusterAddon spec.installNamespace (v1alpha1) <-> installNamespace (v1beta1)
• ManagedClusterAddon status.registrations(v1alpha1) <-> status.registrations (v1beta1)