Removes Endpoint command ref and prebuilt anomaly detection jobs docs

[nastasha-solomon]

Made the following changes:

• Removed the Endpoint command ref and prebuilt anomaly detection jobs docs from the security-docs repo. These files are being moved to the docs-content repo via Adds Endpoint command ref and prebuilt anomaly detection jobs docs docs-content#695.
• Removed refs to the pages from the reference TOC (the docset.yml file)
• Deleted the images folder since the link.svg file is no longer needed for the "Prebuilt jobs" page.

Preview: Reference (note that this section only has the "Prebuilt rule reference"
"Downloadable rule updates" sections)

[github-actions]

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[nastasha-solomon]

I suspect that refs to the prebuilt-anomaly-detection-jobs.md file won't resolve until I merge elastic/docs-content#695. Until I merge that PR, the refs will be pointing to a page that doesn't yet exist.

Edit: Am getting the following error, which I think is the result of what I described above:

'reference/security/prebuilt-anomaly-detection-jobs.md' is not a valid link in the 'docs-content' cross link index: https://elastic-docs-link-index.s3.us-east-2.amazonaws.com/elastic/docs-content/main/links.json

[nastasha-solomon]

run docs-build rebuild

[nastasha-solomon]

Troubleshooting notes for posterity:

The error that was reported earlier indicated that the docs-content repo had links to the deleted prebuilt-jobs.md file. Updating the refs resolved the error and allowed the CI checks for inbound links to pass.