Disconnected user bans

[PowerfulBacon]

If a user is banned while disconnected the following things should happen:

• A database flag should be set which marks the ban as not currently decreasing
• When the user disconnects, the ban should update itself so that it applies from the point of connection
• The user should be informed in an obvious way about the ban. If this is a server ban, then it should be the standard ban message. If this is a role ban it should be a banner in the chat informing the user of their ban.