[Feature] Allow deploying from a given AMI image

Would be nice to be able to deploy the CRC/SNC with a given AMI image ID, instead of letting mapt search from it.

I currently do this with this hacky code:

	// Get AMI
	amiID := os.Getenv("CUSTOM_AMI_ID")
	var ami *ec2.LookupAmiResult
	var err error
	if amiID == "" {
		logging.Info("CUSTOM_AMI_ID not set, searching for the right AMI in AWS ...")
		ami, err = amiSVC.GetAMIByName(ctx,
			fmt.Sprintf("%s*", amiName(r.version, r.arch)),
			[]string{"self", amiOwner},
			map[string]string{
				"architecture": *r.arch})
		if err != nil {
			return err
		}
	} else {
		ami = &ec2.LookupAmiResult{
			Id: amiID, // Your custom AMI ID
		}
	}

which allows me to launch

CUSTOM_AMI_ID=ami-... out/mapt aws openshift-snc create ...

but that could be made more user-friendly

Start at the aws openshift-snc create entry point and trace the AMI lookup around amiSVC.GetAMIByName and amiName, using the issue's CUSTOM_AMI_ID example as context. Define and implement a user-facing way to supply an AMI ID while preserving the existing search behavior, then verify that deployment uses the supplied image.