Provide direct URL to login page

For us that use KeePass/PasswordSafe/browser password store/etc. and don't want to be logged in all the time it would be nice to have a URL pointing directly at the login page, so there is no needless switching (password store to open URL, browser to click login, password store to enter password).

Start by locating the existing login page and its current navigation entry point in the repository. Confirm that a direct URL opens that page without requiring the described navigation steps; the issue is done when users can use that URL to reach login directly.

Written by the indexing model from the issue text.