Support for ed25519 keys

[sdorra]

Proposed changes

Add support for ed25519 ssh keys.

https://groups.google.com/u/1/g/scmmanager/c/0tWi9MZwQ4Q/m/lE8ZOfT2CAAJ

Your checklist for this pull request

• [X] PR is well described and the description can be used as commit message on squash
• [X] Related issues linked to PR if existing and labels set
• [X] Target branch is not master (in most cases develop should bet the target of choice)
• [X] Code does not conflict with target branch
• [X] New code is covered with unit tests
• [X] CHANGELOG.md updated

Checklist for branch merge request (not required for forks)

• [ ] Branch is green/blue on Jenkins
• [ ] Quality Gate passed on SonarQube