Add benchmark suite

It would be good to have a basic benchmark suite to test the performance of the overall stack. I'd like to start with some pretty basic performance tests like maybe:

• Measuring requests per second handled at a few different concurrently levels.
• Run the tests for long enough (maybe 1 minute+) to let some of the async tasks kick in (like log parsing/analytics processing). This isn't the best way to to measure the performance of those aspects, but it would at least sort of get factored into the overall performance by having them running in the background.
• Gather some system metrics while things are being run to try to also ensure changes don't wildly change the system requirements (for example, requiring a lot more memory or eating a lot more cpu). Maybe use something like the jmeter perfmon plugin.

Ideally, benchmarks would be something that would get run on every commit on dedicated hardware so we could track performance of the stack over time and ensure unexpected speed regressions don't happen (something like PyPy's Speed Center). But that's obviously a lot more involved to get setup (dedicated hardware, etc), so I'd like to just start with a basic suite that we could use for comparing things either during development on your own machine.

The issue names no files, tests, or entry points; start by reviewing the repository's existing test and deployment setup alongside the proposed request-concurrency measurements. Define a small local benchmark scope covering sustained runs and system metrics, using the JMeter PerfMon plugin as a possible reference. The per-commit dedicated-hardware setup is explicitly a later goal.