Jenkinsfile: add CI Docker image build for Jenkins

We'll use `deploy-${env}-${stage}` tags for deploy to Spiff envs.

Signed-off-by: Jakub Sokołowski <jakub@status.im>

Jenkinsfile

@@ -0,0 +1,48 @@
+pipeline {
+  agent { label 'linux' }
+
+  options {
+    timestamps()
+    timeout(time: 20, unit: 'MINUTES')
+    buildDiscarder(logRotator(
+      numToKeepStr: '10',
+      daysToKeepStr: '30',
+    ))
+  }
+
+  parameters {
+    choice(
+      name: 'IMAGE_TAG',
+      description: 'Name of Docker tag to push. Chose wisely.',
+      choices: ['latest', 'deploy-app-dev', 'deploy-mod-dev', 'deploy-app-test', 'deploy-mod-test'],
+    )
+    string(
+      name: 'IMAGE_NAME',
+      description: 'Name of Docker image to push.',
+      defaultValue: params.IMAGE_NAME ?: 'statusteam/spiffworkflow-connector',
+    )
+  }
+
+  stages {
+    stage('Build') {
+      steps { script {
+        image = docker.build(
+          "${params.IMAGE_NAME}:${env.GIT_COMMIT.take(8)}",
+          "--label=commit='${env.GIT_COMMIT.take(8)}' ."
+        )
+      } }
+    }
+
+    stage('Push') {
+      steps { script {
+        withDockerRegistry([credentialsId: "dockerhub-statusteam-auto", url: ""]) {
+          image.push()
+          image.push(env.IMAGE_TAG)
+        }
+      } }
+    }
+  } // stages
+  post {
+    always { sh 'docker image prune -f' }
+  } // post
+} // pipeline