Correct structure of website links after migration to folder-based versioning

[morri-son]

Description
After the migration to folder-based versioning the anchors of website links need to be checked and corrected as some contain absolute links (e.g. /docs/some-page) instead of relative links (e.g. docs/some-other-page). This can lead to links referencing across version boundaries.

All links should be converted to Hugo's relref notation using relative links that don't leave version boundaries. relref links are checked by Hugo during build time.

The websites for the ref docs generated for the OCM v1 versioned need to be handled differently. There is already a hack script that changes the pages on each release and adopt it to the website. This hack script needs to be adopted to the new website setup, too.

Done Criteria

• Docs only contain relative pages
• Docs don't link to docs in other versions
• Successful demonstration in Review

[morri-son]

I will start with concentrating on the manually created docs for version "dev" and "legacy". We will remove the "url" from all frontmatters and standardize on Hugos standard link rendering using the file name. For links in manually creted docs we will use Hugo's relref shortcode. It has the advantage that it is checked on build time, so that we can detect broken links before we release a new website version.