Remove deprecated aws cloud-provider helpers functions

[brandond]

The code that sets the correct hostname based on the response from the IMDS is no longer used, due to removal of the in-tree AWS cloud provider in Kubernetes 1.27 and newer.

• rke2/pkg/rke2/rke2_linux.go

  Lines 97 to 108 in 6f1feb7

  	if clx.String("node-name") == "" && cfg.CloudProviderName == "aws" {
  	fqdn := hostnameFromMetadataEndpoint(context.Background())
  	if fqdn == "" {
  	hostFQDN, err := hostnameFQDN()
  	if err != nil {
  	return nil, err
  	}
  	fqdn = hostFQDN
  	}
  	if err := clx.Set("node-name", fqdn); err != nil {
  	return nil, err
  	}

• rke2/pkg/rke2/rke2_linux.go

  Lines 504 to 533 in 6f1feb7

  	func hostnameFromMetadataEndpoint(ctx context.Context) string {
  	ctx, cancel := context.WithTimeout(ctx, time.Second)
  	defer cancel()
  	req, err := http.NewRequestWithContext(ctx, http.MethodGet, "http://169.254.169.254/latest/meta-data/local-hostname", nil)
  	if err != nil {
  	logrus.Debugf("Failed to create request for metadata endpoint: %v", err)
  	return ""
  	}
  	resp, err := http.DefaultClient.Do(req)
  	if err != nil {
  	logrus.Debugf("Failed to get local-hostname from metadata endpoint: %v", err)
  	return ""
  	}
  	defer resp.Body.Close()
  	if resp.StatusCode != http.StatusOK {
  	logrus.Debugf("Metadata endpoint returned unacceptable status code %d", resp.StatusCode)
  	return ""
  	}
  	b, err := ioutil.ReadAll(resp.Body)
  	if err != nil {
  	logrus.Debugf("Failed to read response body from metadata endpoint: %v", err)
  	return ""
  	}
  	return strings.TrimSpace(string(b))
  	}

Attempts to use this code by starting RKE2 with cloud-provider-name: aws will cause the kubelet to fail to start:

E0822 22:35:03.230900     143 run.go:74] "command failed" err="failed to run Kubelet: unknown cloud provider \"aws\""

We should remove this dead code.