IRCv3: Implement the query command

Used /query pidgin2 from a status window and verified it opened a conversation that worked to message pidgin2 by sending messages in the new window. Also used the status window to send /query pidgin2 hiya! and verified that the conversation was created and the message was sent to pidgin2 and that additional messages could be sent from both sides.
I also used /query #pidgin testing against a channel when I was already in #pidgin and verified the message was sent. When using a channel that doesn't exist, the conversation gets created but doesn't work. We should handle this better at some point when we have labelled responses as right now we can't detect the error.
Finally, called in the turtles.