Outgoing new release e-mail notifications were missing links to the
actual release. An example from Codeberg.org e-mail:
<a href=3D"">View it on Codeberg.org</a>.<br/>
This PR adds `"Link"` context property pointing to the release on the
web interface.
The change was tested using `[mailer] PROTOCOL=dummy`.
Signed-off-by: Wiktor Kwapisiewicz <wiktor@metacode.biz>
(cherry picked from commit 37191dcfbdbd007266a4d15a3c85cdf94cec1a7a)