cubicweb-vcreview #3120047 Add a direct link to the "accept" transition [open]

Now that we can read the diff directly in our email, it would be super efficient to have a link to the "accept" transition (https please cf https://www.cubicweb.org/ticket/1679243),

This way one reads the diff in email, clicks the links and accepts the patch instead of having to click the link, click state, click accept, etc.