Optimise the generated clients

[pgressa]

Currently the SdkProcessor generate factory classes for all clients:

@Apis({
        AdmissionregistrationApi.class,
        AdmissionregistrationV1Api.class,
        AdmissionregistrationV1beta1Api.class,
        ApiextensionsApi.class,
        ApiextensionsV1Api.class,
        ApiextensionsV1beta1Api.class,
        ApiregistrationApi.class,
        ApiregistrationV1Api.class,
        ApiregistrationV1beta1Api.class,
        ApisApi.class,
        AppsApi.class,
        AppsV1Api.class,
        AuthenticationApi.class,
        AuthenticationV1Api.class,
        AuthenticationV1beta1Api.class,
        AuthorizationApi.class,
        AuthorizationV1Api.class,
        AuthorizationV1beta1Api.class,
        AutoscalingApi.class,
        AutoscalingV1Api.class,
        AutoscalingV2beta1Api.class,
        AutoscalingV2beta2Api.class,
        BatchApi.class,
        BatchV1Api.class,
        BatchV1beta1Api.class,
        BatchV2alpha1Api.class,
        CertificatesApi.class,
        CertificatesV1beta1Api.class,
        CoordinationApi.class,
        CoordinationV1Api.class,
        CoordinationV1beta1Api.class,
        CoreApi.class,
        CoreV1Api.class,
        CustomObjectsApi.class,
        DiscoveryApi.class,
        DiscoveryV1beta1Api.class,
        EventsApi.class,
        EventsV1beta1Api.class,
        ExtensionsApi.class,
        ExtensionsV1beta1Api.class,
        FlowcontrolApiserverApi.class,
        FlowcontrolApiserverV1alpha1Api.class,
        LogsApi.class,
        NetworkingApi.class,
        NetworkingV1Api.class,
        NetworkingV1beta1Api.class,
        NodeApi.class,
        NodeV1alpha1Api.class,
        NodeV1beta1Api.class,
        PolicyApi.class,
        PolicyV1beta1Api.class,
        RbacAuthorizationApi.class,
        RbacAuthorizationV1Api.class,
        RbacAuthorizationV1alpha1Api.class,
        RbacAuthorizationV1beta1Api.class,
        SchedulingApi.class,
        SchedulingV1Api.class,
        SchedulingV1alpha1Api.class,
        SchedulingV1beta1Api.class,
        StorageApi.class,
        StorageV1Api.class,
        StorageV1alpha1Api.class,
        StorageV1beta1Api.class,
        VersionApi.class,
})
@Singleton
@Internal
final class ApisAutomaticFeatureMetadata {
}

This is quite ineffective so instead use the @ApiClient field or class annotation that will generate the factory class for annotated (in case of field annotation) or all clients found in the classes.