Add support for GCP as a infrastructure provider / if already supported please add clear documentation

[thusharajayakody1]

Your current KubeKey version

v3.1.4

Describe this feature

the ability to provision K3s clusters using gcp as the infrastructure provider

If already supported, add supporting documentation for a clear understanding. as done with other providers

Describe the solution you'd like

the ability to provision K3s clusters using gcp as the infrastructure provider

Additional information

No response