Allow users to connect their own cluster for using Product Analytics. Allow this to be specified at the project-level (rather than group or instance level, which are covered in other epics and issues) Additional context in [parent epic](https://gitlab.com/groups/gitlab-org/-/epics/8921) <!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION --> *This page may contain information related to upcoming products, features and functionality. It is important to note that the information presented is for informational purposes only, so please do not rely on the information for purchasing or planning purposes. Just like with all projects, the items mentioned on the page are subject to change or delay, and the development, release, and timing of any products, features, or functionality remain at the sole discretion of GitLab Inc.* <!-- triage-serverless v3 PLEASE DO NOT REMOVE THIS SECTION -->