Update implementation jobs to use local workflows properly

[avnes]

This pull request updates the GitHub Actions workflows to use local workflow files instead of remote or inline configurations, and makes minor adjustments to scheduling and branch targeting. These changes centralize workflow logic and improve maintainability.

Workflow file refactoring:

• The auto-release job in .github/workflows/implementation-auto-release.yaml now uses the local reusable workflow .github/workflows/automation-auto-release.yml instead of an inline configuration. The branch filter is simplified to only master, and the paths-ignore list is updated to focus on documentation and configuration files.
• The enforce-label job in .github/workflows/implementation-enforce-labels.yaml now uses the local reusable workflow .github/workflows/automation-enforce-release-labels.yml instead of the external enforce-label-action. The branch filter is also simplified to only master.
• The shared job in .github/workflows/implementation-housekeeping.yaml now uses the local reusable workflow .github/workflows/automation-housekeeping.yml instead of the remote dfds/shared-workflows workflow. The housekeeping schedule is changed to run at 2:00 AM UTC instead of 6:00 AM UTC.

[wcarlsen]

That sweet sweet DRY dog fooding. I expect the changes to paths-ignore and cron time makes sense to you ;-)