Welcome/recruitment message

Messages:
- [ ] Create a message that is posted everytime a new user joins in #recruitment telling recruitment officer "hey, this guy joined @recruitment!" (Make sure to detect if the same user leaves within 5 minutes, only after this should the message be sent!)
- [ ] Post recruitment process message on request, applying applicant rank to the user given in the command, also mentioning the user in the message. Command should be something like `!application [@Ford#3939]`. This will then post the application process message that we normally copy paste. Make the "Ford" part optional, instead getting the last message and mentioning the author of that last message instead. If we wanted to be extra fancy, it would grab the last 5 or so messages and check them from most recent to find the user that does not have any tags yet (which is what an applicant would have before this message)