Remaining rough edges in the "chat list" feature

[dx]

• Implement it for some non-purple builtin protocols
• Implement it for bitlbee-facebook
• SIPE support improved, but requires running "chat list" before actually joining channels, which breaks autojoin. Figure out if other protocols have an equivalent issue, or skim the code. I think there was someone in #bitlbee willing to help here.
• Skypeweb joins to a different channel, not the specified one.
• Purple's jabber opens an input query instead of using the server parameter, add a hack for that.