Supplement serde_yaml with a still maintained library

[krucod3]

Description

serde_yaml has been declared deprecated by the maintainer (see https://github.com/dtolnay/serde-yaml/releases/tag/0.9.34)

We should switch to another library at some point, latest when some security issues arise.
I would not hurry this up now, as in my eyes it is still unclear which new library will get good maintenance support.

The maintainer of serde_yaml just suggest to pick one of the currently available crates: https://crates.io/search?q=yaml&sort=relevance

At the moment of writing this, some of the alternatives are:

• https://github.com/sebastienrousseau/serde_yml
• https://crates.io/crates/serde_yaml_ng

As both of the above are quite new, we can wait a bit to see how things evolve.

Goals

Switch to a maintained yaml serialization lib.

Final result

Summary

To be filled when the final solution is sketched.

Tasks

• Task 1
• Task 2
• ...