Add contribution disclaimer partials

What does this MR do and why?

In this MR we're adding a partial that will support adding all of the translated files for the contribution pages for japanese. We've decided not to add any content for the ja-JP contribution section and have it replaced with a disclaimer message instead. Once this MR is merged, we will be pushing all of the following translated files markdown content:

• GitLab: doc/development/
• Runner: docs/development/
• Omnibus: doc/development/
• Charts: doc/development/
• Operator: doc/developer/

More reasoning:

1. If by any means, any japanese user tries to view the contribution pages, we do not want to automatically force the user to an english contribution pages or force them to flip to english. This way, the user can decide to switch to english if they wish to. More details on this and all the relevant discussions have happened here: gitlab-com/localization/docs-site-localization#203 (closed)
2. This MR uses a pattern to control any pages that are under the /ja-jp/development or /ja-jp/runner/development and the partial will be shown at all of these pages under these routes.

See the following comment to learn more about all the upcoming MRs for all of these projects: gitlab-com/localization/docs-site-localization#203 (comment 2534912059)

Related issue: gitlab-com/localization/docs-site-localization#255 (closed)

Screenshots, screen recordings, or links to review app

Any japanese pages under /ja-jp/development or /ja-jp/runner/development will show this alert message.

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.

2. Check out this branch.

3. Visit any available markdown file under /ja-jp/development or /ja-jp/runner/development . Remove the content in it, but leave the header. and visit the page. Note: currently any available japanese markdown file may have some content in them and the alert message will be shown on top of all the content (we'll be removing all of the contents for any markdown files under /development so that they look like the following)

   

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.