Docs: Start converting internal links to antora format

Docs: Start converting internal links to antora format

Links to sections in the same file only need the section ID like this:

xref:#section_id

But links to sections in another file need the Antora page_id also:

xref:MODULE:PAGE.adoc#section_id

Signed-off-by: Remington Steed <rjs7@calvin.edu>