Supporting ovn LB

[garloff]

/kind feature

The quick start guide should mention how to use octavia-ovn as loadbalancer.

Describe the solution you'd like
There's two pieces:

(a) Telling capo to use octavia-ovn.
This one is easy:

spec.topology.variables:
      - name: apiserver_loadbalancer
        value: "octavia-ovn"

(b) Telling OCCM to create OVN LBs when asked to create LBs
This one requires tweaking the helm chart in templates/_helpers.tpl:

[LoadBalancer]
manage-security-groups=true
#enable-ingress-hostname=true
create-monitor=true
lb-provider=ovn
lb-method=SOURCE_IP_PORT