gitlab-ci: Parametrize the osname and handle authenticated access

Make the downstreams' life easier by making the osname a parameter that can be easily customized instead of hardcoding apertis in multiple places.

When retrieving the artifacts, pass the job token so that things work fine even for downstreams requiring authenticated access.

restored source branch wip/em/parametrize-and-auth

added 3 commits

• 8e2879d0 - gitlab-ci: Move branch lists at the top for customizability
• 729d5d18 - gitlab-ci: Do not split a for loop over multiple strings
• 90f45c62 - gitlab-ci: Handle authenticated access

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added 1 commit

• dc09cb49 - 1 commit from branch main

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merged