profiles: introduce DisplayNames

This is exactly the same as the DisplayName enum in Damus iOS. Due to
the various inconsistencies in `name` and `display_name` between
clients, we have to generalize DisplayName into two variants: one name
or two names.

If we have two names, we treat it in the standard way of display_name is
the real name, and `name` is the username.

If only one is set, then it is considered both the username and "real name".

Signed-off-by: William Casarin <jb55@jb55.com>

src/lib.rs

@@ -31,6 +31,7 @@ mod test_utils;
 
 pub use app::Damus;
 pub use error::Error;
+pub use profile::DisplayName;
 
 #[cfg(target_os = "android")]
 use winit::platform::android::EventLoopBuilderExtAndroid;