Update u2f to 0.2, which requires OpenSSL but also might solve the problems we've had with certificates.

The rust image doesn't need installing curl or tar, so removed. Also collapsed ENV lines.

src/api/core/two_factor/u2f.rs

@@ -92,6 +92,7 @@ struct RegistrationDef {
     key_handle: Vec<u8>,
     pub_key: Vec<u8>,
     attestation_cert: Option<Vec<u8>>,
+    device_name: Option<String>,
 }
 
 #[derive(Serialize, Deserialize)]