Jenkins config nodejs

- added nodejs plugin and config

Jenkinsfile

@@ -5,16 +5,20 @@ pipeline {
         stage('Stylecheck') {
         steps {
             echo 'Checking Style...'
+            nodejs {
                 sh 'npm i'
                 sh 'npm i tslint --dev'
                 sh 'tslint src/**/*.ts'
             }
         }
+        }
         stage('Build') {
             steps {
                 echo 'Building...'
+                nodejs {
                     sh 'ng build --prod'
                 }
             }
         }
     }
+}