Automatic merge from submit-queue (batch tested with PRs 52013, 56719). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.
Support autoprobing floating-network-id for openstack cloud provider
Currently if user doesn't specify floatingnetwork-id and loadbalancer.openstack.org/floating-network-id annotation, openstack cloud provider can't create a external LoadBalancer service.
Actually we can get floatingnetwork-id automatically.
If we get multiple floatingnetwork-ids, then ask user to specify one, or we use the floatingnetwork-id to create floatingip for external LoadBalancer service.
This is a part of #50726
**Special notes for your reviewer**:
/assign @dims
**Release note**:
```release-note
Support autoprobing floating-network-id for openstack cloud provider
```
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