chore(ci): reuse discord send function from library

No need to keep an almost identical copy here.

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

ci/Jenkinsfile.release

@@ -1,3 +1,6 @@
+#!/usr/bin/env groovy
+library 'status-jenkins-lib@v1.8.6'
+
 pipeline {
   agent { label 'linux' }
 
@@ -98,10 +101,10 @@ pipeline {
 
   post {
     success { script {
-      def discord = load "${WORKSPACE}/ci/discord.groovy"
       discord.send(
-        header: 'Nim-Waku deployment successful!',
+        header: '**Nim-Waku deployment successful!**',
         cred: 'discord-waku-deployments-webhook',
+        descPrefix: "Image: [`${IMAGE_NAME}:${IMAGE_TAG}`](https://hub.docker.com/r/${IMAGE_NAME}/tags?name=${IMAGE_TAG})"
       )
     } }
     always { sh 'docker image prune -f' }