merge-queues

Within S-CORE there are probably several approaches already implemented on how to do merge queues. And maybe even more exist.

Collect best practices. Identify best approach. Set up discussions as required.

This will solve:
* QNX builds in PRs
* Mandatory cheks

AC:
* Clear guidance for repos on how to set up merge queues

Optional:
* set it up in cicd-action, cicd-workflows, docs-as-code, score or some other repos
* prepare jsonnet "function" (something convinient) how to apply merge queue config to a repo

Ref:
* repos that have merge queues
* https://github.com/eclipse-score/.eclipsefdn/blob/main/otterdog/eclipse-score.jsonnet (search for required_merge_queue)
* old attempt see https://github.com/eclipse-score/.eclipsefdn/pull/174/changes
* https://github.com/eclipse-score/.eclipsefdn/pull/214/changes

Start by reviewing repositories that already use merge queues, then inspect required_merge_queue in .eclipsefdn/otterdog/eclipse-score.jsonnet and the changes in pull requests 174 and 214. Compare the approaches, identify the preferred setup, and document clear guidance for repositories; any optional configuration in cicd-action, cicd-workflows, docs-as-code, score, or Jsonnet should be treated separately.

Written by the indexing model from the issue text.