How do I configure a phone number format?
In short - you can't.  Phone numbers are entered as free entry text.  That's different from addresses, where the format is about which order different fields fall in; phone numbers are only one field.  Dates aren't stored as freeform text; they're stored in a specialized "date" field to handle this.

That said, there's an extension called CiviDesk Normalize, and one of its functions is to store the phone numbers in a uniform format.  However, you don't get to choose the format (except "National" or "International" style).  

From the code: 


  INTERNATIONAL and NATIONAL formats are consistent with
  the definition in ITU-T Recommendation E123.


If you have access to a developer who knows PHP, they can probably edit the format with a line or two of code - but I suspect it's more important that the phone numbers be uniform than the actual formatting!