Add a callback URL when using /logout

When calling /logout on a Nuxeo server:

• the Nuxeo session is invalidated
• the authentication plugin used to log in the user tries to handle the logout also
• if the authentication plugin did not redirect, there is a redirect done on the startup page.

Handle a new callbackUrl parameter when calling /logout that will be used to redirect the user if the authentication plugin did not do the redirect.
Limit the URLs to be redirected to:

• URL starting with the server base URL
• URL starting with Nuxeo Drive and Nuxeo Mobile custom protocols.

If the callbackUrl does not match any of the limits, ignore it.