Provide multiple options for greeting users

[daydr3am3r]

The following would be appreciated:

1. Have an option to send either a private to users joining the channel or a channel greeting message
2. Have an option to turn the greeting on or off

Do these make sense?

[gehaxelt]

Hi, thanks for the suggestion. However, I can't promise that I'll find time for that before the end of the year.

PRs are always welcome ;)