chore: remove old Jenkins pipeline config

Jenkinsfile

@@ -1,38 +0,0 @@
-pipeline {
-  environment {
-    registry = 'https://registry.hub.docker.com'
-    registryCredential = 'dockerhub_jcabillot'
-    dockerImage = 'jcabillot/calibre'
-  }
-
-  agent any
-
-  triggers {
-    cron('@midnight')
-  }
-
-  stages {
-    stage('Clone repository') {
-      steps{
-        checkout scm
-      }
-    }
-
-    stage('Build image') {
-      steps{
-        sh 'docker build --force-rm=true --no-cache=true --pull -t ${dockerImage} .'
-      }
-    }
-
-    stage('Deploy Image') {
-      steps{
-        script {
-          withCredentials([usernamePassword(credentialsId: 'dockerhub_jcabillot', usernameVariable: 'DOCKER_USER', passwordVariable: 'DOCKER_PASS')]) {
-            sh 'docker login --username ${DOCKER_USER} --password ${DOCKER_PASS}'
-            sh 'docker push ${dockerImage}'
-          }
-        }
-      }
-    }
-  }
-}