Replace Go model generation for open-cluster-management

[manusa]

Description

Part of #6130

Replace model generation for open-cluster-management module with new OpenAPI approach.

Note

For extension models there are going to be multiple conflicts with the previously generated code.

Tasks

• Remove build-helper-maven-plugin
• Remove maven-antrun-plugin from the generate profile
• Remove jsonschema2pojo-maven-plugin from the generate profile
• Consolidate all extension models to the same module (certmanager, tekton, and so on all have multiple model generator modules)
• Configure the openapi-model-generator-maven-plugin plugin to generate the specific classes.
• Remove the go-related files and directories (Makefile, cmd)
• Remove invocation from the generateModel.sh script

[manusa]

• Request to extend model to cover ACM #3506
• Fix #3506: Add Extension for Open Cluster Management #3641

Models:
https://docs.redhat.com/en/documentation/red_hat_advanced_cluster_management_for_kubernetes/2.3/html/apis/apis#rhacm-docs_apis_cluster_jsondeletecluster
#3506 (comment)

Group	URL
agent.open-cluster-management.io	https://github.com/stolostron/klusterlet-addon-controller/tree/main/pkg/apis/agent/v1
app.k8s.io	https://github.com/kubernetes-sigs/application/tree/master/api/v1beta1 extremely deprecated
apps.open-cluster-management.io	- https://github.com/open-cluster-management-io/multicloud-operators-channel/tree/main/pkg/apis/apps/v1 - https://github.com/open-cluster-management-io/multicloud-operators-subscription/tree/main/pkg/apis/apps/v1 - https://github.com/stolostron/multicloud-operators-placementrule/tree/main/pkg/apis/apps extremely deprecated - https://github.com/stolostron/multicloud-integrations/tree/main/pkg/apis/apps extremely deprecated
cluster.open-cluster-management.io	https://github.com/open-cluster-management-io/api/tree/main/cluster
discovery.open-cluster-management.io	https://github.com/stolostron/discovery/blob/main/api/
observability.open-cluster-management.io	https://github.com/stolostron/multicluster-observability-operator/tree/main/operators/multiclusterobservability/api
operator.open-cluster-management.io	- https://github.com/stolostron/multiclusterhub-operator/tree/main/api/v1 - https://github.com/open-cluster-management-io/api/tree/main/operator/v1
policy.open-cluster-management.io	https://github.com/stolostron/governance-policy-propagator/tree/main/api
search.open-cluster-management.io	- https://github.com/stolostron/search-operator/tree/main/api/v1alpha1 extremely deprecated - https://github.com/stolostron/search-v2-operator