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
```