Remove broken "linkinator" link checker

[morri-son]

Description
Due to constant failures from network related issues with the linkinator link checker, we will remove the link checker completely. Any internal direct links on the website will be replaced by Hugo's relref shortcode which will be checked for existance during Hugo built-time.

Done Criteria

• workflow removed

[jakobmoellerdev]

@morri-son this is missing:

1. If we need this issue
2. Where the parent EPIC is (link is missing)
3. You mentioned this as linked in a PR but I think they are maybe even unrelated, please clean this up

Thanks