Require password to edit, delete, create reservations

[milotoor]

There is currently (weak; see #2) security around fetching the full details of existing reservations, but there is no password required to create, edit or delete a reservation. Editing and deleting requires having an existing reservation's ID, which can't be obtained without the password; nevertheless it's poor form to have these endpoints unsecured.

• Refactor the router to be a class with add, edit, delete, get and getBasic methods.
• Write a decorator function require_auth which can wrap the above methods to secure them. The logic for this function can be taken from the current get_reservations file.
• Apply the new decorator to the add, edit, delete and get methods.