Provide event to allow changing tab complete response from servers

Adds the ServerTabCompleteEvent which is fired upon receiving a TabCompleteResponse packet from a server to the client.
The purpose of this event is to be able to change the results of a tab complete after the request has been processed by the target server.

Use case:
We use this on our server to block people from tab completing the names of currently vanished players in either commands, or in chat.