Support AUTHENTICATE DIGEST-MD5 for OMTP visual voicemail

As specified in https://www.ietf.org/rfc/rfc2831.txt

+ use the SSL port in the carrier config for IMAP SSL connection
+ avoid server capabilities that is disabled in carrier config.
+ Additional config for T-Mobile

Fixes:27816895
Change-Id: Ic3d29f3ea388242d37646e9c9c76f14ee54e41c2
(cherry picked from commit 44cabbb246ed3ce7830a4730d941c4355d569ed0)
8 files changed