Move backend source to server/ subpackage

To clarify the organization.

server/src/domain/opaque_handler.rs

@@ -0,0 +1,36 @@
+use super::error::*;
+use async_trait::async_trait;
+
+pub use lldap_auth::{login, registration};
+
+#[async_trait]
+pub trait OpaqueHandler: Clone + Send {
+    async fn login_start(
+        &self,
+        request: login::ClientLoginStartRequest,
+    ) -> Result<login::ServerLoginStartResponse>;
+    async fn login_finish(&self, request: login::ClientLoginFinishRequest) -> Result<String>;
+    async fn registration_start(
+        &self,
+        request: registration::ClientRegistrationStartRequest,
+    ) -> Result<registration::ServerRegistrationStartResponse>;
+    async fn registration_finish(
+        &self,
+        request: registration::ClientRegistrationFinishRequest,
+    ) -> Result<()>;
+}
+
+#[cfg(test)]
+mockall::mock! {
+    pub TestOpaqueHandler{}
+    impl Clone for TestOpaqueHandler {
+        fn clone(&self) -> Self;
+    }
+    #[async_trait]
+    impl OpaqueHandler for TestOpaqueHandler {
+    async fn login_start(&self, request: login::ClientLoginStartRequest) -> Result<login::ServerLoginStartResponse>;
+    async fn login_finish(&self, request: login::ClientLoginFinishRequest ) -> Result<String>;
+    async fn registration_start(&self, request: registration::ClientRegistrationStartRequest) -> Result<registration::ServerRegistrationStartResponse>;
+    async fn registration_finish(&self, request: registration::ClientRegistrationFinishRequest ) -> Result<()>;
+    }
+}