Better handling for session expiration

[kquick]

This topic may need some discussion and therefore need to be migrated to the wiki, but MatterMost has a session length limit (see below), after which Matterhorn will receive and print "Invalid or expired session, please login again." for any activity. At present, this requires exiting and restarting Matterhorn. This issue represents a concern that this could be handled better by Matterhorn, providing the direct ability to re-login or some other way to refresh the session length.

Session Length AD/LDAP and Email (days):
30
The number of days from the last time a user entered their credentials to the expiry of the user's session. After changing this setting, the new session length will take effect after the next time the user enters their credentials.

[kquick]

Also worth noting: once the session has expired, Matterhorn will no longer get and display channel updates so new messages on these channels are not highlighted or otherwise indicated and things appear "quiet" when this might not actually be the case. We may want to consider having Matterhorn have a more active indicator (notification) of when a session has expired so that people relying on notifications aren't silently affected by this.

[jtdaugherty]

Revisiting this, I'm wondering if this has been resolved since it was opened. Although I don't usually run Matterhorn long enough to risk running into this issue, I know a number of our regular users do and they haven't reported it. (They report other problems that come up in long-running Matterhorn processes...) I'm inclined to close this unless you're aware of any outstanding problems here.