Support easily adding braavos accounts the same we do for argentx

[antazoey]

Overview

Have an enum value for the class hash so users dont have to know it

Specification

Describe the syntax and semantics of how you would like to see this feature implemented. The more detailed the better!

Remember, your feature is much more likely to be included if it does not involve any breaking changes.

Dependencies

Include links to any open issues that must be resolved before this feature can be implemented.