Add JSON schema metadata for Sitelinks search box

What does this MR do and why?

Updates to schema.org metadata, which is used in search results on google.com:

• Re-adds Website information. This used to exist on the site, but it was reformatted in 9ac5ca8f and removed entirely in e24d9c43. This metadata is required for Google to show a Sitelinks Searchbox (docs).
• Updates Organization information: removes an old address and updates the logo image. Since we're not GitLab's primary website, we don't really need to provide every single attribute of this (it may not be used at all, we'll see!).
• Removes the schema file from the /search page. It needs to only be present on the homepage per step 2 here: https://developers.google.com/search/docs/appearance/structured-data/sitelinks-searchbox#adding-structured-data

Issue here: #167 (closed)

Screenshots, screen recordings, or links to review app

These are strongly recommended to assist reviewers and reduce the time to merge your change.

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

1. Configure a local GitLab Docs environment: https://gitlab.com/gitlab-org/gitlab-docs/-/blob/main/doc/setup.md.
2. Inspect HTML on the homepage to view the JSON data.

Merge request acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this merge request.

Closes #167 (closed)