Removed useless old stuff (mainly old comments)
The method get_user was rewritten to be clearer.
Implemented _PUBLIC_ROUTES

The sequence _PUBLIC_ROUTES was created to handle public requests.
Public requests don’t need a logged user to be dispatched
Moved templates

Templates have been moved to templates directory.
Implemented public handler - for questions only

and also
- changed MainHandler to forward URL redirection (for example, unlogged
user accessing private page - should be redirected after login)
- render_template method had a redundant call to get_user
- start to implement Note class