/kind feature

Describe the solution you'd like
I'm attempting to spin up a cluster that is entirely on a private network that has already been created. Unfortunately, I'm met with a uniqueness error:

"error":"failed to reconcile network for HetznerCluster rbjorklin-com/rbjorklin-com: failed to create network: error creating network: name is already used (uniqueness_error)"

Anything else you would like to add:
I have created a network with a single VM inside it. From this VM I'm attempting to bootstrap a cluster with a private-only network. Does this make sense? Do you foresee any issues doing this?

Environment:

• cluster-api-provider-hetzner version: v1.0.0-beta.15
• Kubernetes version: v1.26.3
• OS (e.g. from /etc/os-release): Fedora 37