Adding website endpoint as stored attribute

Adding the website endpoint associated with each bucket as a stored attribute
Side note: this logic is challenging to reason about. Would it make sense to move the `new_resource.enable_website_hosting` check into `compare_website_configuration` (seems like that's a valid difference) and rename  that to `website_configuration_changed?` ? (i.e if previously it was disabled and now it's enabled, or vice versa, then it's a change in the config otherwise we don't care, right?) It would make this a lot easier to read... I think.