Return keys listing in auth options

src/data/admin.rs

@@ -2,6 +2,8 @@
 //!
 //! @author Pierre Hubert
 
+use webauthn_rs::proto::Credential;
+
 #[derive(Copy, Clone, Eq, PartialEq, Debug, Hash)]
 pub struct AdminID(u64);
 
@@ -41,7 +43,7 @@ pub struct AdminKey {
     pub id: u64,
     pub admin_id: AdminID,
     pub name: String,
-    pub key: String,
+    pub key: Credential,
 }
 
 /// Admin access token