doc(self-managed): rework the references of camunda release and namespaces

[leiicamundi]

Description

Following camunda/camunda-deployment-references#250, we have reworked our usage of the namespace and helm release name across our documentation and script.

This PR apply this update by extracting some hard coded namespace values and release names

I've also reverted the reference of rosa-8.8 as we should now use main branch of https://github.com/camunda/camunda-deployment-references for any 8.8 target

When should this change go live?

• This is a bug fix, security concern, or something that needs urgent release support. (add bug or support label)
• This is already available but undocumented and should be released within a week. (add available & undocumented label)
• This is on a specific schedule and the assignee will coordinate a release with the Documentation team. (create draft PR and/or add hold label)
• This is part of a scheduled alpha or minor. (add alpha or minor label)
• There is no urgency with this change (add low prio label)

PR Checklist

• My changes are for an upcoming minor release and are in the /docs directory (version 8.8).
• My changes are for an already released minor and are in a /versioned_docs directory.

• I added a DRI, team, or delegate as a reviewer for technical accuracy and grammar/style:
  • Engineering team review
  • Technical writer review via @camunda/tech-writers unless working with an embedded writer.

[github-actions]

👋 🤖 🤔 Hello, @leiicamundi! Did you make your changes in all the right places?

These files were changed only in docs/. You might want to duplicate these changes in versioned_docs/version-8.7/.

• docs/self-managed/setup/deploy/amazon/openshift/terraform-setup.md

You may have done this intentionally, but we wanted to point it out in case you didn't. You can read more about the versioning within our docs in our documentation guidelines.

[leiicamundi]

@camunda/tech-writers could you please proceed to the review and release a doc version as some files requires updates on stable 8.7 of the doc

[christinaausley]

Would you consider this name change a breaking change? I would likely add this to https://docs.camunda.io/docs/reference/announcements-release-notes/overview/.

Also, you checked the box that this is part of a scheduled alpha or minor, but I don't see a label attached to this PR. What alpha or minor is this specific to?

[leiicamundi]

Hi @christinaausley,

We don't consider it as a breaking change as the user was not relying on that specific variable previously.
The checkbox was a mistake, sorry.

[github-actions]

The preview environment relating to the commit 8ac3b1c has successfully been deployed. You can access it at https://preview.docs.camunda.cloud/pr-5626/