Docs: Add missing redirects to /workflow and /articles docs

What does this MR do?

Many docs are moved, and the old location has a simple This document was moved... line and the redirect_to frontmatter to automatically push the users to the right page (saving a click). Unfortunately, not all docs have the automatic redirect, forcing users to drop into a holding page, then click through.

This MR adds the redirect_to frontmatter to all moved docs in /workflow and /articles that are missing it.

Related issues

https://gitlab.com/gitlab-com/gitlab-docs/issues/349

Author's checklist

• Follow the Documentation Guidelines and Style Guide.
• Link docs to and from the higher-level index page, plus other related docs where helpful.
• Apply the ~Documentation label.

Review checklist

All reviewers can help ensure accuracy, clarity, completeness, and adherence to the Documentation Guidelines and Style Guide.

1. Primary Reviewer

• Review by a code reviewer or other selected colleague to confirm accuracy, clarity, and completeness. This can be skipped for minor fixes without substantive content changes.

2. Technical Writer

• Optional: Technical writer review. If not requested for this MR, must be scheduled post-merge. To request for this MR, assign the writer listed for the applicable DevOps stage.

3. Maintainer

1. Review by assigned maintainer, who can always request/require the above reviews. Maintainer's review can occur before or after a technical writer review.
2. Ensure a release milestone is set and that you merge the equivalent EE MR before the CE MR if both exist.
3. If there has not been a technical writer review, create an issue for one using the Doc Review template.

doc/articles/artifactory_and_gitlab/index.md

+---
+redirect_to: '../../ci/examples/artifactory_and_gitlab/index.md'
+---
+
 This document was moved to [another location](../../ci/examples/artifactory_and_gitlab/index.md)