Add indicator to contributor doc pages

What does this MR do and why?

Closes #1327 (closed)

Adds a tier-badge-style indicator to Contributor docs to help distinguish them as dev docs.

Paths that start with these URL patterns are considered developer docs and given this new badge:

• /ee/development/
• /omnibus/development/
• /runner/development/
• /charts/development/

Contributor docs should not have regular pricing/tier badges, but if they do, the new badge will sit to the right side of the other badge.

Screenshots, screen recordings, or links to review app

Before	After

Examples

Some pages with the new badge:

• https://sarahg-contribute-indicator.docs.gitlab-review.app/ee/development/
• https://sarahg-contribute-indicator.docs.gitlab-review.app/runner/development/add-windows-version.html
• https://sarahg-contribute-indicator.docs.gitlab-review.app/ee/development/api_graphql_styleguide.html

Pages without the "Contribute" badge (unchanged):

• https://sarahg-contribute-indicator.docs.gitlab-review.app/ee/integration/akismet.html
• https://sarahg-contribute-indicator.docs.gitlab-review.app/ee/install/
• https://sarahg-contribute-indicator.docs.gitlab-review.app/ee/user/application_security/

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. Check out this branch and compile the site: make compile.
3. View the site (make view) and visit pages within the development sections to view the new badge. Check a few pages in other non-developer sections to verify the badge does not appear there.

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.