fix: reduce cyclomatic complexity 34 in VEXXHOST provisioner

The VEXXHOST provisioner has a function with a very high cyclomatic

```shell
pkg/cloud/vexxhost/vexxhost.go:96:1: cyclomatic complexity 34 of func `(*VEXXHOST).CreateServer` is high (> 30) (gocyclo)
func (v *VEXXHOST) CreateServer(args automation.ServerArgs) (*automation.RessourceResults, error) {
```

We should split the fn to reduce the complexity