Currently the link is always the website link once website_portal or
website_quote is installed. However it is better to use the generic
/mail/view controller that chooses the right redirection depending on
the user trying to access the document.
This commit also fixes redirection in website_quote that is always
redirecting to the front-end. Classic users should land on the backend.
Indeed seeing the front-end page is rarely interesting for them.
Thibault Delavallée
b49da62365