docs: add persisted query configuration options info

[Meschreiber]

This PR adds information about persisted queries router configuration options. The "security levels" or "modes" were already documented, but this adds reference information about the individual options. I've purposefully put them after the modes, since those are likely to be more useful to readers.

I'm targeting main since this is only a docs change. LMK if that's not right.

[router-perf]

CI performance tests

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

[Meschreiber]

Thanks for reviewing @Geal and @bnjjj . It looks like this and one other docs PR (cc @smyrick ) are failing CI checks and therefore can't be merged. Not sure why .mdx only changes would cause that. Would you be able to take a look whenever you get a chance? TIA!

[Geal]

@Meschreiber all PRs have to target dev, because we have a release process that's a bit complex and breaks if a commit goes directly to main without going in dev first.
The docs change fail CI because we have a test that goes through the configuration examples in the docs and validates them with the router's code. For #3613, it was failing because the configuration requires an environment variable that the test process does not know about.
For this PR it fails with could not deserialize configuration: apqs must be disabled to enable safelisting: either set preview_persisted_queries.safelist.enabled: false or apq.enabled: false in your router yaml configuration

So I think it requires this configuration for the safelist examples:

preview_persisted_queries:
  enabled: true
  safelist:
    enabled: true
apq:
  enabled: false

[Geal]

@Meschreiber sorry, I reconfirmed out of band: it's fine to push a documentation update directly to main, we'll handle it during the release process

[Meschreiber]

The docs change fail CI because we have a test that goes through the configuration examples in the docs and validates them with the router's code. For #3613, it was failing because the configuration requires an environment variable that the test process does not know about.

Ah neat, thanks for fixing that and suggesting the fix for this one!