Strict WebDav clients cannot connect to Tuleap webdav server when it's configured as a sub-url of the main domain name (eg. https://tuleap.example.com/plugins/webdav as opposed to https://webdav.tuleap.example.com) this is due to the old way of managing URLs based on apache/nginx locations that mandate the final / on the location.

This is legacy and thankfully, nowadays it's no longer mandatory as we can define our own URL scheme with fastroute (request #13030).

Thanks to front router, when WebDav is configured to run on main domain name, the url should no longer be customizable (ie it will be fixed to /webdav prefix) and it will be served by front router.

This fix compatibility with nautilus.