ImageCreateWizard: Use imageOutputStepMapper in all imageOutput steps

Also renamed the stepMapper to clarify that it's just meant for the
imageOutput steps.

src/Components/CreateImageWizard/steps/stepMapper.js

@@ -1,15 +0,0 @@
-export default ({ 'target-environment': targetEnv, release } = {}, { skipAws, skipGoogle, sipAzure } = {}) => {
-    if (!skipAws && targetEnv?.aws) {
-        return 'aws-target-env';
-    }
-
-    if (!skipGoogle && targetEnv?.google) {
-        return 'google-cloud-target-env';
-    }
-
-    if (!sipAzure && targetEnv?.azure) {
-        return 'ms-azure-target-env';
-    }
-
-    return release === 'rhel-8' ? 'registration' : 'packages';
-};