[triggers] Add keyword triggers
Please add to Triggers plugin that it can recognize some keyword, as then it is possible to launch external command, and use gajim-remote to return back some information to user who launched it. This implies that username must be passed to environment somehow, like %u for external command to work.
This feature can then enable many other goodies such as that user can send message, and receive list of pending task or current to-do list or get contact information from external programs and other features.