Adding a Google Cloud Provider and the ocp4-cluster as gcp enabled (#1244)
* Adding a Google Cloud Provider and the ocp4-cluster as gcp enabled
* Making gcloud use ENV variables with a unique temp directory
* cleaning up a redundant set_fact and fixing a bug in azure_infra deploy which got exposed during the same test cycle
* making ssh keys autogenerate and add admin keys to hosts in Azure and GCP
* Ensuring a user specified key could still be used on Azure or GCP
* adding osp_ssh_config_setup.yml even though it isn't used