CI template sentry application

What does this MR do?

Adds a new CI template to Sentry as a cluster application.

Based on this MR: !20822 (merged)

• This has the advantage of surfacing install logs to the user
• Also, this has the feature of allowing users to customize the installation via helm values

Related to: #26513 (closed)

Still TODO

• Merge Cluster Applications code and increment tag (gitlab-org/cluster-integration/cluster-applications!11 (merged))
• Use new tag value in Managed-Cluster-Applications.gitlab-ci.yml

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content