Add support for LB in upcloud private zone

[davidumea]

What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind api-change

/kind bug /kind cleanup /kind design /kind documentation /kind failing-test /kind feature /kind flake

What this PR does / why we need it:

When provisioning Load Balancers in UpCloud private cloud zones, the Load Balancer needs to sit in the public equivalent zone.

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Does this PR introduce a user-facing change?:

Add support for LB in UpCloud private zone