Merge branch 'l_conditional_stage' into 'master'

Add conditional stage for scripted pipelines

See merge request sysadmins/jenkins-adminsLib!12

Author: lamaral

vars/when.groovy

@@ -0,0 +1,20 @@
+#!/usr/bin/groovy
+
+// Kindly borrowed from: https://github.com/comquent/imperative-when
+// MIT License
+// Copyright 2018 by Comquent GmbH
+
+import org.jenkinsci.plugins.pipeline.modeldefinition.Utils
+
+def call(boolean condition, body) {
+    def config = [:]
+    body.resolveStrategy = Closure.OWNER_FIRST
+    body.delegate = config
+
+    if (condition) {
+        body()
+    } else {
+        Utils.markStageSkippedForConditional(STAGE_NAME)
+    }
+}
+