Port/reconcile upgrade functionality to CE

Problem

We have helm upgrade related functionality in EE so that Prometheus can add/update remove alerts. We will not have a good time when we develop upgrade of GitLab Managed apps in CE and have to reconcile the two.

Proposal

Port the following from EE:

• EE extension to BaseHelmService
• EE extension to Clusters::Applications::Prometheus. Allow #upgrade_command to optionally replace values.
• Reconcile: Prometheus#upgrade_command and Prometheus#install_command
• Reconcile: cluster_upgrade_app_worker.rb and cluster_update_app_worker.rb
  • PrometheusUpdateService minus update_config which is EE specific
• Reconcile: CheckInstallationProgressService and CheckUpgradeProgressService
• Reconcile ClusterWaitForAppInstallationWorker and ClusterWaitForAppUpdateWorker

The above are enabling the gitlab-ce~2278657 functionality of Prometheus alerting but are also generic type functionality which we will use to upgrade all GitLab Managed apps.