ECDSA JWT

[afflerbach]

Now supports JWT with ES-256, ES-384 and ES-512 algorithms.

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Reviewer checklist

• Read PR description: a summary about the changes is required
• Changelog updated
• Documentation: docs/{Reference, Cli, ...}, Docker and cli help/usage
• Pulled branch, manually tested
• Verified requirements are met
• Reviewed the code
• Reviewed the related tests

[malud]

We could take the chance and solve some code todos :)

Resolved…