[ocp4_workload_openshift_gitops] Add new variable ocp4_workload_openshift_gitops_api_version

[agonzalezrh]

SUMMARY

Currently is difficult to specify directly the api_version, as you need to specify the internal variable (_ocp4_workload_openshift_gitops_api_version). This PR is to add a new variable called ocp4_workload_openshift_gitops_api_version and if doesnt exist it is using _ocp4_workload_openshift_gitops_api_version

ISSUE TYPE

• Feature Pull Request

COMPONENT NAME

ocp4_workload_openshift_gitops role