Rename "jahresrückblick-open-elements-2024"

[hendrikebbers]

You can find the post at https://open-elements.com/posts/2025/01/16/jahresrückblick-open-elements-2024/ and https://open-elements.com/de/posts/2025/01/16/jahresrückblick-open-elements-2024/

The "ü" in the post name makes a. lot of problems since links often look broken. we should rename it to "open-elements-2024" and the official urls should be https://open-elements.com/posts/2025/01/16/open-elements-2024/ and https://open-elements.com/de/posts/2025/01/16/open-elements-2024/

While that will make the link much better we need to be able to support the old URL since pages already link to it. We should check if Hugo has the possibility to do it (see https://gohugo.io/content-management/urls/#aliases) or if we need to do it in a different way.

[hendrikebbers]

Example of the negative effect of that URL