Implement npmExecuteScripts step (#1422)

vars/npmExecuteScripts.groovy

@@ -0,0 +1,23 @@
+import com.sap.piper.DownloadCacheUtils
+import groovy.transform.Field
+
+import static com.sap.piper.Prerequisites.checkScript
+import static groovy.json.JsonOutput.toJson
+
+@Field String STEP_NAME = getClass().getName()
+@Field String METADATA_FILE = 'metadata/npmExecuteScripts.yaml'
+
+//Metadata maintained in file project://resources/metadata/npmExecuteScripts.yaml
+
+void call(Map parameters = [:]) {
+    final script = checkScript(this, parameters) ?: this
+
+    // No credentials required/supported as of now
+    List credentials = []
+
+    parameters['dockerOptions'] = DownloadCacheUtils.getDockerOptions(script)
+    if (DownloadCacheUtils.isEnabled(script)) {
+        parameters['defaultNpmRegistry'] = DownloadCacheUtils.getNpmRegistryUri(script)
+    }
+    piperExecuteBin(parameters, STEP_NAME, METADATA_FILE, credentials)
+}