Route quote calls through the center

[BillHodghead]

From @bhcrosslake on April 26, 2017 23:39

As part of threat modeling we determined that routing the quoting and invoice calls through the center may help to:

• Allow the center to help identify fraudulent invoices
• Log the quote and invoice calls in a central place for later auditing

As part of the threat model, we recommend the quotes and invoices route through centrally. This story adds to that to a simple logging service in the center.

Copied from original issue: LevelOneProject/Docs#465
See question: LevelOneProject/Docs#336

[BillHodghead]

Waiting on #336

[BillHodghead]

From @emschwartz on May 23, 2017 8:11

The ILP components are no longer involved in the end-to-end communication

[BillHodghead]

With the elimination of the SPSP protocol, much of the original story no longer makes sense. I've cut this back to a logging issue for potential future work.