feat: add groovy class

vars/buildahExecute.groovy

@@ -0,0 +1,10 @@
+
+import groovy.transform.Field
+
+@Field String STEP_NAME = getClass().getName()
+@Field String METADATA_FILE = 'metadata/buildahExecute.yaml'
+
+void call(Map parameters = [:]) {
+    List credentials = []
+    piperExecuteBin(parameters, STEP_NAME, METADATA_FILE, credentials)
+}