OCP on Openstack: lbFloatingIP to apiFloatingIP

[clopnis]

Describe the bug
From OCP 4.7 apiFloatingIP is used instead of lbFloatingIP

To Reproduce
Check in template on agnosticd, in commit upstream on OpenShift and README

1. https://github.com/redhat-cop/agnosticd/blob/development/ansible/roles/host-ocp4-installer/templates/install-config.yaml.j2#L152
2. openshift/installer@712799d
3. https://github.com/openshift/installer/blame/release-4.7/docs/user/openstack/README.md

Verions (please complete the following information):

• OCP > 4.6
• cloud provider openstack

[agonzalezrh]

@clopnis sorry I didnt receive notifications about issues, can you open a PR?