feat(build): add Jenkinsfile.

Jenkinsfile

+/*
+** Variables.
+*/
+properties([buildDiscarder(logRotator(numToKeepStr: '50'))])
+def serie = '20.10'
+def maintenanceBranch = "${serie}.x"
+if (env.BRANCH_NAME.startsWith('release-')) {
+  env.BUILD = 'RELEASE'
+} else if ((env.BRANCH_NAME == 'master') || (env.BRANCH_NAME == maintenanceBranch)) {
+  env.BUILD = 'REFERENCE'
+} else {
+  env.BUILD = 'CI'
+}
+def featureFiles = []
+
+/*
+** Pipeline code.
+*/
+stage('Source') {
+  node {
+    sh 'setup_centreon_build.sh'
+    env.WIDGET = 'global-health'
+    dir("centreon-widget-${env.WIDGET}") {
+      checkout scm
+    }
+    sh "./centreon-build/jobs/widgets/${serie}/widget-source.sh"
+    source = readProperties file: 'source.properties'
+    env.PROJECT = "${source.PROJECT}"
+    env.VERSION = "${source.VERSION}"
+    env.RELEASE = "${source.RELEASE}"
+    env.SUMMARY = "${source.SUMMARY}"
+    publishHTML([
+      allowMissing: false,
+      keepAll: true,
+      reportDir: 'summary',
+      reportFiles: 'index.html',
+      reportName: 'Centreon Build Artifacts',
+      reportTitles: ''
+    ])
+  }
+}
+
+try {
+  stage('Package') {
+    parallel 'centos7': {
+      node {
+        sh 'setup_centreon_build.sh'
+        sh "./centreon-build/jobs/widgets/${serie}/widget-package.sh centos7"
+      }
+    },
+    'centos8': {
+      node {
+        sh 'setup_centreon_build.sh'
+        sh "./centreon-build/jobs/widgets/${serie}/widget-package.sh centos8"
+      }
+    }
+    if ((currentBuild.result ?: 'SUCCESS') != 'SUCCESS') {
+      error('Package stage failure.');
+    }
+  }
+
+  if ((env.BUILD == 'RELEASE') || (env.BUILD == 'REFERENCE')) {
+    stage('Delivery') {
+      node {
+        sh 'setup_centreon_build.sh'
+        sh "./centreon-build/jobs/widgets/${serie}/widget-delivery.sh"
+      }
+      if ((currentBuild.result ?: 'SUCCESS') != 'SUCCESS') {
+        error('Delivery stage failure.');
+      }
+    }
+  }
+} catch(e) {
+  if ((env.BUILD == 'RELEASE') || (env.BUILD == 'REFERENCE')) {
+    slackSend channel: "#monitoring-metrology",
+        color: "#F30031",
+        message: "*FAILURE*: `CENTREON WIDGET GLOBAL HEALTH` <${env.BUILD_URL}|build #${env.BUILD_NUMBER}> on branch ${env.BRANCH_NAME}\n" +
+            "*COMMIT*: <https://github.com/centreon/centreon-widget-global-health/commit/${source.COMMIT}|here> by ${source.COMMITTER}\n" +
+            "*INFO*: ${e}"
+  }
+
+  currentBuild.result = 'FAILURE'
+}