Add service monitor for jenkins

Add service monitor resource for jenkins prometheus endpoint.

Please follow up https://github.com/kubesphere/kubesphere/issues/3814.

PR https://github.com/kubesphere/ks-jenkins/pull/27 is an upstream of the current one. And I've provided an docker image for demo show: johnniang/ks-installer:jenkins-monitoring.

/kind feature /area devops

What's changed?

• Add ServiceMonitor for monitoring Jenkins prometheus endpoint.
• Add Jenkins alert rules(custom rule) for alerting when something went wrong.
• Add kubesphere-devops-worker namespace for Jenkins agent.
• Add quota setting on kubesphere-devops-worker namespace and optimize Jenkins casc configuration.