docs: update router containerization and deployment content

[shorgi]

Updated and reorganized Containerization content, primarily rewriting Kubernetes topic as quickstarts and short examples to deploying router on k8s with Helm.

Previews:

• Containerization overview
• Deploy in Kubernetes
• Run in Docker

[router-perf]

CI performance tests

• events_big_cap_high_rate - Stress test for events with a lot of users, deduplication enabled and high rate event with a big queue capacity
• events_without_dedup - Stress test for events with a lot of users and deduplication DISABLED
• events - Stress test for events with a lot of users and deduplication ENABLED
• large-request - Stress test with a 1 MB request payload
• step - Basic stress test that steps up the number of users over time
• xlarge-request - Stress test with 10 MB request payload
• reload - Reload test over a long period of time at a constant rate of users
• no-graphos - Basic stress test, no GraphOS.
• xxlarge-request - Stress test with 100 MB request payload
• step-jemalloc-tuning - Clone of the basic stress test for jemalloc tuning
• const - Basic stress test that runs with a constant number of users

[garypen]

I've left some comments mainly for discussion when we meet later.

[garypen]

Big steps in the right direction. I'll try and get the Rhai bits written tomorrow, but it is more likely to end up being next week.

[Meschreiber]

Great additions @garypen and @shorgi ! 👏👏👏

I've included inline copy suggestions and have these general remarks:

• Love that you've moved config files to shared content for reusability. Within the content of a page, does it generally make sense to hide them in ExpansionPanels? In some cases you're already doing this, and I'm wondering if there are other places it makes sense too, e.g. https://deploy-preview-3943--apollo-router-docs.netlify.app/containerization/kubernetes#deploy-with-a-coprocessor
• Structure on most pages makes sense. On the Docker page, the intro paragraph doesn't align with section headers:

It would be nice to get them a little more aligned. (E.g., make Running the debug container to investigate memory issues an H3, add Specifying the supergraph to the intro.)

Finally, though not (yet) included on this PR, the Passing command-line arguments to the Router binary and Debugging your container sections could use a little copyediting love too (if time permits).

E.g. The first sentence of Passing command-line arguments to the Router binary is a little hard to follow: "By default, the router command invoked inside the published container does run not set any of the available command-line options."

And for Debugging your container, it would be best to avoid using terms like "easy" or "simply" when giving users instructions.

PS. Apologies for starting this review with one-off suggestions instead of incorporating them all here. Was still drinking my morning coffee! 😅

[shorgi]

I've included inline copy suggestions and have these general remarks:

Thanks @Meschreiber for your thoughtful and thorough review 🙏 ! I've addressed all of your suggestions and general remarks.

[garypen]

I opened a replacement PR: #4001, so that we can target these changes to main. Closing this one so it doesn't get merged by mistake.