Docs: update o11y and query plans for beta

[robertjdominguez]

Description

This PR updates the o11y section for Beta by doing the following:

• Changes the top-level directory from observability to query-plan
• Moves docs for the Explain API from graphql-api to query-plan
• Adds screenshot for query and SQL execution in the console

DOCS-1814

Quick Links 🚀

• Explain API

[cloudflare-workers-and-pages]

Deploying v3-docs with    Cloudflare Pages

Latest commit:	841d5f8
Status:	⚡️  Build in progress...

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[robertjdominguez]

Redirects 🔀

Hey, @robertjdominguez & @seanparkross — the following redirects will be needed for deployment:

# TEST ME: https://stage.hasura.io/docs/3.0/graphql-api/explain/_category_.json
location = /docs/3.0/graphql-api/explain/_category_.json {
    return 301 https://$host/docs/3.0/OG-FILE-WAS-DELETED-REPLACE-ME-WITH-NEW-LOCATION;
}

# TEST ME: https://stage.hasura.io/docs/3.0/graphql-api/explain/api-reference/
location = /docs/3.0/graphql-api/explain/api-reference/ {
    return 301 https://$host/docs/3.0/observability/explain/api-reference/;
}

# TEST ME: https://stage.hasura.io/docs/3.0/graphql-api/explain/index/
location = /docs/3.0/graphql-api/explain/index/ {
    return 301 https://$host/docs/3.0/observability/explain/index/;
}

[robertjdominguez]

Hey, @robertjdominguez 👋

Thanks for this PR! Since you changed docs files, our automated Action assigned Rob as your reviewer 🎉

Before Rob looks over the changes, we ask you to take care of a couple of items:

• Make sure you've checked over our PR guide on the wiki. It ensures you've done your due diligence on the basics: spelling, heading casings, etc.
• Rob will need a review from someone on your team to ensure your team-specific content is accurate. Once that's done, ping Rob on Slack, and he'll give a docs review 🔥
• Additionally, please check this box to confirm your feature works as expected when using the documentation you've written. This is critical to ensuring our users have the information they need.

The docs team aims to get all PRs reviewed within 48 hours of your team doing a review in the form of a content pass. Let Rob know the level of urgency on Slack 👍

[robertjdominguez]

Images automagically compressed by Calibre's image-actions ✨

Compression reduced images by 47.8%, saving 181.42 KB.

Filename	Before	After	Improvement	Visual comparison
static/img/explain/0.0.1_console_explain-api-sql.png	379.58 KB	198.16 KB	-47.8%	View diff

58 images did not require optimisation.

[seanparkross]

🚀