docs(self-managed): update OpenShift routes instructions

[hamza-m-masood]

Description

Related issue: https://github.com/camunda/distribution/issues/253 This PR updates the OpenShift routes page for 8.5.

When should this change go live?

• [ ] This is a bug fix, security concern, or something that needs urgent release support.
• [x] This is already available but undocumented and should be released within a week.
• [ ] This on a specific schedule and the assignee will coordinate a release with the DevEx team. (apply hold label or convert to draft PR)
• [ ] This is part of a scheduled alpha or minor. (apply alpha or minor label)
• [ ] There is no urgency with this change and can be released at any time.

PR Checklist

• [x] My changes are for an already released minor and are in /versioned_docs directory.
• [ ] My changes are for the next minor and are in /docs directory (aka /next/).

• [x] My changes require an Engineering review, and I've assigned the Engineering DRI or delegate.
• [x] My changes require a technical writer review, and I've assigned @camunda/tech-writers as a reviewer.

[github-actions[bot]]

:wave: :robot: :white_check_mark: Looks like the changes were ported across versions, nice job! :tada:

You can read more about the versioning within our docs in our documentation guidelines.

[hamza-m-masood]

The connector changes are only being added to 8.5 since within 8.6, zeebe gateway will have full support for rest. I will then open another PR to recommend the customer to use rest in zeebe gateway when openshift routes are configured. I can only create that PR once I have tested 8.6 zeebe.

[hamza-m-masood]

@conceptualshark Please wait for @aabouzaid to approve the PR before you start your review. Thanks.

[akeller]

This PR updates the OpenShift routes page for 8.5.

Is there anything in this PR that should be ported to 8.6 (/next/)?

[aabouzaid]

@akeller No change in the content, so Hamza will copy the same content to other versions once all reviewers are done.