Models/Auth: Replace some hardoced messages

Signed-off-by: ZorEl212 <[email protected]>

models/exception/auth.py

@@ -1,10 +1,11 @@
 #!/usr/bin/env python3
 
+import resources.strings as strings
 class AuthenticationError(Exception):
     def __init__(self, message, err_code):
         self.message = message
         self.err_code = err_code
 
     def __str__(self):
-        return f"AuthenticationError: {self.message}"
+        return f"{strings.EXC_AUTH_ERROR}: {self.message}"