Fix internal broken links

[a-m-zill]

Because we have changed the structure there are still a lot of broken links in the documentation.
Find them and repair this under this issue.

Thx.

[javahippie]

Will take care of this

With these config settings, the build fails when detecting a broken link:

  onBrokenLinks: 'throw',
  onBrokenMarkdownLinks: 'throw',