Feature: move `shared_automatic_event_join_toggle` to General tab of Prefs

[hughlilly]

I think this option belongs below the "Send notification to join next event meeting…” option on the General tab, instead of on the Advanced tab. I don’t think it’s a particularly advanced feature (or at least it’s arguably not in the same league as AppleScript and regex controls). I think particularly if a user sets this option and then a while later wants to turn it off, they might naturally look for it alongside the “Send notification…” option.

[jgoldhammer]

What do you think @leits ? I have no specific preference.