Add comprehensive tests for mentor repository and authentication

- Implemented tests for creating, retrieving, updating, and deleting mentors in `mentor_repository_test.rs`.
- Added tests for user authentication, including successful login, invalid email formats, and inactive users in `auth_login_tests.rs`.
- Created a mock test environment setup in `mock_test.rs` to facilitate database operations during tests.
- Updated module structure to include new test files for mentors and authentication.
- Ensured cleanup of the database after tests to maintain isolation and prevent side effects.

imphnen-libs/src/argon/mod.rs

@@ -1,9 +1,9 @@
 use argon2::{
-	password_hash::{
-		rand_core::OsRng, Error, PasswordHash, PasswordHasher, PasswordVerifier,
-		SaltString,
-	},
 	Argon2,
+	password_hash::{
+		Error, PasswordHash, PasswordHasher, PasswordVerifier, SaltString,
+		rand_core::OsRng,
+	},
 };
 
 pub fn hash_password(password: &str) -> Result<String, Error> {