apidoc: Fix some issues regarding generated documentation links

Previous URLs targetting endpoints documentation were in the form
/1/<endpoint_route> while they should have been in the form
/api/1/<endpoint_route> so fix them and add redirections from old
URLs for backward compatibility.

Breadcrumbs located in the top left part of Web API endpoint doc
could contain links to non existent endpoints so ensure to remove
those and render spans instead.