ZOOKEEPER-3896: Migrate Jenkins jobs to Jenkinsfile based Pipeline

As part of the new CI instance migration we wanted to take advantage of Jenkinsfile based pipelines. From now on we're able to script and source control our main Jenkins settings.

This patch only adding the Jenkinsfile itself to all major branches: master, branch-3.6 and branch-3.5. Once it's in I'll create the Jenkins job which will use it.

Currently I have a testing job based on my ZK fork: https://ci-hadoop.apache.org/view/ZooKeeper/job/zookeeper-master-maven-multipipeline/

Author: Andor Molnar <andor@apache.org>

Reviewers: Enrico Olivelli <eolivelli@apache.org>

Closes #1409 from anmolnar/ZOOKEEPER-3896

Jenkinsfile

@@ -0,0 +1,71 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+pipeline {
+   agent none
+
+    options {
+        buildDiscarder(logRotator(daysToKeepStr: '14'))
+    }
+
+    triggers {
+        pollSCM 'H/10 * * * *'
+        cron('@daily')
+    }
+
+    stages {
+        stage('Prepare') {
+            matrix {
+                agent any
+                axes {
+                    axis {
+                        name 'JAVA_VERSION'
+                        values 'JDK 1.8 (latest)', 'JDK 11 (latest)'
+                    }
+                }
+
+                tools {
+                    // Install the Maven version configured as "M3" and add it to the path.
+                    maven "Maven (latest)"
+                    jdk "${JAVA_VERSION}"
+                }
+
+                stages {
+                    stage('BuildAndTest') {
+                        steps {
+                            // Get some code from a GitHub repository
+                            git 'https://github.com/apache/zookeeper'
+
+                            // Run Maven on a Unix agent.
+                            sh "mvn verify spotbugs:check checkstyle:check -Pfull-build -Dsurefire-forkcount=4"
+                        }
+                        post {
+                            // If Maven was able to run the tests, even if some of the test
+                            // failed, record the test results and archive the jar file.
+                            always {
+                               junit '**/target/surefire-reports/TEST-*.xml'
+                               archiveArtifacts '**/target/*.jar'
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
+