Integrate gitlab-ci/fix-confluence-missing-mx6-section and 1 more

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@ab19eb61

CI: collect_release_information: jump to next pipeline if no deploy jobs found

See for error:
https://git.seco.com/seco-ne/yocto/infrastructure/ci-test/minimal-manifest/-/jobs/828261

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Commit: seco-ne/yocto/infrastructure/gitlab-ci@ae764fbc

CI: Confluence page: Fix not created mx6 section

The function that merges the variables of the different jobs, i.e:

`MACHINE="mx6"`

`MACHINE="mx6ull"`

used python `in` to check if a value already exists.
But `"mx6" in "mx6ull"` is true, so mx6 was dropped.
This rewrites it, storing the variables in a set (which is unique
automatically) instead of space seperated strings.
Space seperation is added before printing the variables to be used on
on the shell.