Localization support

Localization support. Finnish language added as a second language for the system. Also fixed an issue that could have shown direct error messages to the end users.

Needs testing before merge

src/tjts5901/auth.py

@@ -117,6 +117,10 @@ def get_user_by_email(email: str) -> User:
 
 @bp.route('/register', methods=('GET', 'POST'))
 def register():
+    """
+    Function that handels registration and checks if
+    everything is inputed properly.
+    """
     if request.method == 'POST':
         print("Registering user...")
         email = request.form['email']