Improve port number warnings

The SSL/TLS/STARTTLS distinction appears to be a non-negligible source
of confusion. This patch tries to improve this by emphasizing the
correct, standard port number a bit more and identifying the cnryption
method at the same time.

Change-Id: Iefff721796d7308e45be69e7e19a0c540e63312d
CCBUG: 404211