Introduce prometheus federator test framework

[alexandreLamarre]

The test framework aims to address the following issues:

• Parallelization : run integration tests in parallel
• Idempotent : can be run multiple times with the same inputs and environment, and it will always produce the same result—pass or fail—without side effects.
• Filterable : run isolated problematic test cases on demand
• Reproducible : when a test fails, can directly inspect resources in the remote environment
• Debug-able : can enter the debugger to isolate behavior
• Direct code coverage
• Data driven : Run the same tests with different inputs and expect the same behavioral result based on inputs
• Extensible : Drop-in adding of test cases to common setup

Some high level goals, that don't necessarily pertain to test-strategy

• Work-around existing code structure, without functionality & refactors to enable testability
• Allow for future refactors to improve stability, and better reproducibility of bugs

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