add proper onboarding when phil is added to a new server

[ahlec]

• When he joins a server, have him set up the server config
• When he joins a server, have him set up the appropriate chronos automatically
• When he joins a server, have him DM the person who added him (or the server creator)
  • Allow for a one-time setting of the command prefix via DM
  • Allow for a one-time setting of the admin role via DM
  • Provide a walkthrough of Phil's features (how to use p!config and p!enable/etc)