Jenkinsfile: Add timeout and retry to be more resilient

After a recent kernel update on the workers we've been hitting issues that cause jobs to get stuck or fail:

• fakemachine dying with no trace: https://jenkins.apertis.org/job/apertis-v2020/job/images/job/debos-image-build/151/execution/node/1038/log/
• kernel in fakemachine getting stuck in crypto_wait_for_test: https://jenkins.apertis.org/job/apertis-v2019/job/images/job/debos-image-build/299/execution/node/262/log/

Set a timeout to cause the bigger jobs to fail after 30 minutes with no new output in the logs and then tell Jenkins to automatically retry them.

Test Jenkins pipeline: https://jenkins.apertis.org/job/playground/job/em/job/debos-image-build/4/flowGraphTable/