Build infrastructure for running performance tests on rust-vmm crates

[alxiord]

Add a dedicated Buildkite pipeline for performance tests for each crate that has such tests (alongside the "standard" CI pipeline). In the future, this can help separate performance runs from build / CI runs, and split tests on different machines according to our needs.

It's worth looking into critcmp as it seems easy to run and get a verdict from.

Long term, long duration performance tests will demand separate runs (nightly / on some other schedule). To begin with, we can add performance tests in the CI because:

• it's easier to add them there short term
• it will give us early indicators of how long they take
• it will help us assess the stability of results

[alxiord]

See https://github.com/rust-vmm/rust-vmm-container/issues/27 for additions to the rust-vmm-container

[andreeaflorescu]

Let's keep this issue open until we add the performance pipeline to the rust-vmm-ci instead of having it duplicated in all repositories that require performance tests.

[alxiord]

test_benchmark.py is part of rust-vmm-ci now. Closing.