Draft: Resolve "CI: solve TODO about automating changelog update in release notes"

Closes #597

See https://gitlab.isc.org/isc-projects/stork/-/jobs/2036221 and /data/shared/sweng/stork/releases/0.21.0-test for a succesful deployment. If this MR gets merged or closed, /data/shared/sweng/stork/releases/0.21.0-test can be deleted.

The job above was tested with branch 597-ci-solve-todo-about-automating-changelog-update-in-release-notes of stork.wiki which would have to be merged. What does this is rename Release-notes-x.y.md to Release-notes-x.y.z.md. This is for easier recognition of the version and to avoid conflicts with different patch version but same major and minor versions. I don't think there are links saved to the release notes that will be invalidated. On FTP, the entire text is uploaded. Plus, this is better done earlier than later.

This MR also fixes this line that wouldn't have worked when we moved to 1.x versions:

fold -sw 73 < stork.wiki/*eleases/*${stork_version_minor}.md
Edited by Andrei Pavel

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