Meta topic: https://meta.discourse.org/t/full-name-at-sign-up-went-missing/345662/17?u=osama
The preloaded `site` object for anons on login-required sites is a stripped down version of the full object with just a specific set of attributes and doesn't use the site serializer. This results in the `full_name_required_for_signup` and `full_name_visible_in_signup` attributes not making it to the client app when a login-required site is accessed by an anon, causing the name field in the signup form to not be rendered, even when it's required.
This commit includes those attributes in the stripped down version of the `site` object that's used for anons on login-required sites.
This adds dedicated routes for /login and /signup, replacing the use of modals. Currently, this is behind the experimental_full_page_login feature flag. It also includes some small consistency fixes related to formatting, spacing, icons, and the loading of certain elements
