[FIX] mail, mass_mailing: do not add a link to access the document
when the email is not a notification, or not an email usign the automatic
threading. This means that when doing mass mailing with a fixed reply_to
there won't be any link to access the original document, which is what
we want. Otherwise when mailing partners, they have a link to access
their own partner profile, which does not make sense.
[FIX] web: CharDomain form widget: fixed change selection
button not correctly displayed depending on the effective_readonly
parameter. It is now correctly computed.

Also added a link to see records when in view mode, instead of not
being able to see the selection if not in edit mode.