Reference ID Exchange

[sunmilee]

https://github.com/diem/dip/blob/main/dips/dip-183.md

[davidiw]

DIP-183 needs to be updated with this feedback:

Considering the general direction here, I'd actually propose a bit of rework in DIP-183 in particular with examples and test data.

Examples which could go into the appendix include various different strategies for exchanging a reference id:

Subaddresses
PayString
Other naming services
Leveraging Diem domain identifiers in addition to other services
Then we could avoid introducing a new naming construct that is Diem specific and altogether unnecessary.

In addition, we should have good test cases for verifying correctness of the exchange.