Dev: Cluster Test Dataset in Test ENV

**Describe the task**
Deploy a database cluster in `test` that mirrors prod data. We should be able to selectively deploy a pull request into the test environment that uses the `test` data cluster.

**Acceptance Criteria**
- [ ] Test database cluster should bootstrap from prod pgbackrest repo (can we use a separate pgbackrest repo to isolate prod data?)
- [ ] Deploying the test database cluster should bootstrap from the the latest prod pgbackrest repo, this could be a separate repo from prod's active repo, and any test env writes would be also it's own repo.
- [ ] third

**Additional context**
- Add any other context about the task here.
- Or here

No files, tests, or entry points are named. Start by locating the test-environment deployment configuration and the pgBackRest repositories, then clarify whether test data must use a separate repository and replace the placeholder acceptance criterion. Done means a test database cluster can bootstrap from the latest appropriate production backup without mixing test writes into production data.

Written by the indexing model from the issue text.